Imagine waking up to the aroma of a hearty, savory breakfast, already prepared and simply waiting to be baked. This Sausage and Mushroom Breakfast Casserole is precisely that dream come true. Combining the rich flavors of browned sausage and earthy mushrooms with fluffy eggs, savory cheese, and a luscious homemade mushroom gravy, this casserole is a true showstopper. It’s not just a meal; it’s a comforting experience, ideal for bustling holiday mornings, leisurely weekend brunches, or any special occasion where you want to impress without the stress. Crafted to be assembled the night before, it offers unparalleled convenience, allowing you to savor precious moments with loved ones while a delightful feast bakes to golden perfection.
This particular casserole holds a special place in my heart, rooted in cherished childhood memories. Every Christmas morning, after the excitement of unwrapping presents, my family would gather at my grandparents’ home. Without fail, my grandma would have her legendary sausage and mushroom breakfast casserole, hot and steaming from the oven, awaiting our arrival. That distinct savory flavor, the tender bread, and the creamy texture became synonymous with festive joy and familial warmth.
Inspired by those treasured mornings, I’ve lovingly recreated her iconic recipe. While I’ve introduced a few contemporary twists to enhance its flavors and simplify the process, the essence remains perfectly preserved. It captures that same comforting, satisfying taste I remember so vividly, making it an indispensable savory make-ahead breakfast for any significant gathering. This isn’t just a recipe; it’s a culinary legacy, bringing generations together around the breakfast table with every delicious bite.
Watch How to Make This Casserole!
Table of Contents
Why You’ll Adore This Make-Ahead Breakfast Casserole
This isn’t just any breakfast casserole; it’s a culinary masterpiece that promises to become a cherished tradition in your home. The irresistible combination of savory elements — juicy breakfast sausage, earthy sautéed mushrooms, fragrant onions, and gooey melted cheddar cheese — creates a symphony of flavors in every bite. It’s a hearty and satisfying dish that truly elevates any morning meal.
What truly sets this casserole apart and gives it its signature depth and richness is the incredibly creamy mushroom gravy. Unlike many casseroles that can dry out, this decadent gravy blankets the ingredients, ensuring every forkful is moist, tender, and bursting with flavor. While my grandmother, with her practical wisdom, often used a can of cream of mushroom soup for convenience, I’ve opted to craft my gravy from scratch. This homemade approach allows for a fresher, more nuanced flavor profile that truly shines. However, rest assured, both options yield a wonderfully delicious result, catering to your preference for homemade goodness or time-saving ease.
Beyond its exceptional taste, the sheer convenience of this make-ahead breakfast casserole makes it a favorite among busy hosts and hostesses. The ability to assemble the entire dish the night before means you can enjoy a leisurely morning, free from last-minute cooking stress. Simply slide it into the oven when you wake, and let the magic happen. This flexibility makes it an absolute essential for holiday breakfasts like Christmas or Thanksgiving, celebratory brunches, or any occasion where you desire a delicious, homemade meal without the morning rush. It’s a wonderful way to treat your family and guests to a memorable breakfast with minimal effort on the day of.
“This is by far, the best version of this egg-with-bread-in-the-bottom casserole I have tried. The taste is exquisite. My entire family loved it, so no leftovers, darn it.” — A delighted reader, KJT
Essential Ingredients for Your Savory Breakfast Casserole
Crafting this incredible sausage and mushroom breakfast casserole requires a selection of fresh, high-quality ingredients that harmonize beautifully to create its signature flavor. Each component plays a vital role, from the foundational bread to the rich, creamy gravy. Below is a detailed list of what you’ll need, with some notes to help you choose the best:
- Butter: Essential for sautéing the vegetables and creating the roux for the gravy, butter adds richness and depth.
- Ground Breakfast Sausage: Opt for a flavorful breakfast sausage. You can choose mild or spicy, depending on your preference. Ground pork sausage is traditional, but turkey or chicken sausage can also be used for a lighter option.
- Mushrooms: Button, cremini (baby bella), or a mix of your favorite fresh mushrooms will work perfectly. Slicing them uniformly ensures even cooking.
- Onion: A medium yellow or white onion, finely chopped, provides aromatic sweetness that balances the savory elements.
- Cheddar Cheese: Freshly shredded sharp or mild cheddar cheese melts beautifully and adds a tangy, salty counterpoint. For best results, shred your own cheese from a block.
- Eggs: Large eggs form the custardy base of the casserole, binding all the delicious components together.
- Bread: Sturdy white bread, such as French bread, artisan loaf, or even day-old brioche, is ideal. Cut into cubes, it absorbs the egg mixture without becoming overly soggy. Stale bread works even better!
- Milk: Whole milk or 2% milk is recommended for the egg mixture and gravy, providing richness and a creamy texture.
- All-Purpose Flour: Used to create the roux, the thickening agent for our exquisite homemade mushroom gravy.
- Salt and Pepper: Fundamental seasonings to enhance all the natural flavors of your ingredients. Adjust to your taste preferences.
- Fresh Chives: An optional but highly recommended garnish, fresh chopped chives add a vibrant pop of color and a mild oniony freshness that brightens the entire dish.
Step-by-Step Guide: Crafting Your Sausage and Mushroom Breakfast Casserole
Creating this delicious make-ahead breakfast casserole is a straightforward process, but paying attention to each step ensures a perfect, flavorful result. Follow these detailed instructions for a memorable breakfast:
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1. Prepare the Sausage, Mushrooms, and Onions:
Begin by browning the ground breakfast sausage in a large, heavy-bottomed skillet over medium-high heat. Break it apart with a spoon as it cooks, ensuring it’s evenly browned and thoroughly cooked through. Once done, remove the sausage from the skillet and set it aside, leaving any residual drippings in the pan – these will add flavor to your vegetables.
Next, add 2 tablespoons of butter to the same skillet. Once melted, add the sliced mushrooms and chopped onions. Season lightly with a pinch of salt and pepper. Sauté, stirring occasionally, for about 5-7 minutes, or until the mushrooms have released their moisture and turned golden brown, and the onions are soft and translucent. Remove the cooked vegetables from the skillet and combine them with the browned sausage.
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2. Whisk Up the Rich Mushroom Gravy:
Using the same skillet (no need to clean it!), melt the remaining 2 tablespoons of butter over medium heat. Sprinkle in the all-purpose flour, and whisk continuously for about 1 minute to create a “roux.” This cooked flour and butter paste will be the base for your creamy gravy. Gradually pour in 1 cup of milk while vigorously whisking to prevent lumps. Continue to whisk and simmer the mixture until it thickens to a smooth, velvety consistency, typically taking 3-5 minutes. Season the gravy generously with 1 teaspoon of salt and ¼ teaspoon of black pepper, or adjust to your taste. Set this flavorful homemade mushroom gravy aside.
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3. Assemble Your Breakfast Casserole:
Lightly grease a 9×13-inch baking dish. Spread the cubed French bread (or other chosen white bread) into an even layer across the bottom of the prepared dish. In a separate large bowl, whisk together the 12 large eggs, the remaining 1 cup of milk, and the ¼ cup of melted butter. Add ½ teaspoon of salt and ¼ teaspoon of black pepper to the egg mixture. Carefully pour this egg mixture evenly over the bread cubes, ensuring all pieces are thoroughly moistened. This step is crucial for a non-dry casserole.
Next, scatter the cooked sausage, mushrooms, and onions evenly over the egg-soaked bread. Sprinkle half of the shredded cheddar cheese over this layer. Finally, spoon the rich mushroom gravy in heavy drizzles over the entire casserole, creating pockets of flavor. Top with the remaining half of the shredded cheese. Gently press down on the ingredients with the back of a spoon to ensure everything is submerged and evenly distributed, preventing any dry bread spots.
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4. Chill for Optimal Flavor (Make-Ahead Step):
This is where the “make-ahead” magic happens! Cover the assembled casserole dish tightly with aluminum foil and transfer it to the refrigerator. Allow it to chill for a minimum of 4 hours, or ideally, overnight (up to 24 hours). This crucial chilling period allows the bread cubes to fully absorb the egg mixture, resulting in a perfectly custardy texture and ensuring all the flavors meld beautifully.
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5. Bake to Golden Perfection:
When you’re ready to bake, preheat your oven to 350°F (175°C). Place the chilled casserole directly into the preheated oven, keeping it covered with foil. Bake for approximately 45-60 minutes. After about 35-45 minutes, remove the foil and continue baking for another 10-15 minutes, or until the casserole is beautifully puffed, golden brown on top, and completely set in the middle. To check for doneness, gently shake the dish; there should be no jiggly parts in the center. An internal temperature of 160°F (71°C) with an instant-read thermometer also confirms it’s ready.
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6. Garnish and Serve:
Once baked, remove the casserole from the oven and let it rest for 5-10 minutes. This brief resting period allows the casserole to set further and makes for cleaner slices. If desired, sprinkle generously with freshly chopped chives for a burst of color and a fresh, subtle oniony flavor. Slice into generous portions and serve hot. Get ready for rave reviews!
Expert Tips for a Perfect Breakfast Casserole
To ensure your Sausage and Mushroom Breakfast Casserole turns out absolutely perfect every time, consider these invaluable tips and tricks:
- Mastering the Make-Ahead Advantage: While it is technically possible to bake this casserole immediately after assembly, for the absolute best texture and flavor, chilling it for at least 4 hours is highly recommended. This allows the bread cubes ample time to fully absorb the rich egg and milk mixture, preventing a dry casserole and ensuring a wonderfully moist, custardy interior. Preparing it the night before (up to 24 hours in advance) is the ideal strategy for busy mornings. When it’s baking time, simply transfer the covered dish directly from the refrigerator to your preheated oven – no need to bring it to room temperature first. This convenience is what makes it the best make-ahead breakfast casserole for holidays and special gatherings.
- Gravy Customization: Homemade vs. Canned: The homemade mushroom gravy truly elevates this dish, offering a fresh and deeply flavorful profile. However, if time is of the essence or you prefer the classic simplicity of my grandma’s original method, a can of cream of mushroom soup is a perfectly acceptable substitute. Just be sure to warm it slightly before spooning it over the casserole to achieve a smoother, more spreadable consistency. This ensures even distribution and prevents any dense, cold clumps in your dish.
- Creative Flavor Variations & Dietary Adaptations: Breakfast casseroles are incredibly versatile, making them perfect for customization! Don’t hesitate to experiment with different types of cheese – Monterey Jack, Gruyere, or a Swiss blend would all be delicious. For a vegetarian option, simply omit the sausage. If you’d like a leaner protein, ground turkey or chicken sausage can be used. Boost the vegetable content by incorporating sautéed spinach (ensure it’s well-drained), diced bell peppers, or even a handful of sun-dried tomatoes. If mushrooms aren’t your favorite, feel free to leave them out entirely or substitute with another vegetable you enjoy.
- Ensuring Perfect Doneness: The key to a perfectly cooked breakfast casserole is knowing when it’s done without overbaking. The casserole should be beautifully puffed and golden brown on top. The most reliable test is to gently shake the baking dish; if the center is completely set with no visible “jiggle,” it’s ready. An instant-read thermometer inserted into the center should register 160°F (71°C) for food safety and optimal texture.
- Storing and Reheating Leftovers: This sausage and mushroom breakfast casserole is fantastic for leftovers, making it even more practical! To reheat the entire dish, cover it with foil and warm in a 300°F (150°C) oven for about 25-30 minutes, or until heated through. Individual slices can be easily reheated in the microwave for a quick breakfast or snack. Store any leftover casserole tightly covered in the refrigerator for up to 3-4 days.
Serving Suggestions and Accompaniments
This hearty Sausage and Mushroom Breakfast Casserole is incredibly satisfying on its own, but for special occasions, holiday brunches, or when entertaining a larger crowd, pairing it with complementary sides can create a truly spectacular spread. Here are some delightful recommendations to serve alongside your savory casserole:
Additional Breakfast Pairing Ideas:
- Crispy Bacon or Ham: While the casserole has sausage, extra crispy bacon strips or thinly sliced baked ham can always add more protein and flavor.
- Coffee & Juice: A pot of freshly brewed coffee, alongside a selection of juices (orange, cranberry, apple), is essential for any breakfast or brunch spread.
- Light Green Salad: For a lighter contrast, a simple green salad with a vinaigrette dressing can cut through the richness.
- Yogurt Parfaits: Layered with granola and berries, yogurt parfaits offer another fresh and healthy option.
Explore More Make-Ahead Breakfast Delights
If you appreciate the convenience and deliciousness of make-ahead breakfasts, you’ll love these other recipes that streamline your morning routine:
- Baked French Toast with Streusel Topping and Cranberry Maple Syrup:A sweet and comforting option that’s perfect for a crowd.
- Spinach and Tomato Baked Egg Cups:Individual portions of fluffy eggs, ideal for meal prep and quick grab-and-go breakfasts.
- Asparagus, Bacon and Cream Cheese Quiche:A sophisticated and savory tart that’s fantastic hot or cold.
- Raspberry Almond Baked Oatmeal:A wholesome and fruity baked oatmeal that’s nutritious and satisfying.
The Full Recipe Card
Rating: 5 out of 5 stars from 3 reviews
Sausage and Mushroom Breakfast Casserole
Servings: 12 servings
Prep Time: 30 mins
Cook Time: 45 mins
Chill Time: 4 hrs
Total Time: 5 hrs 15 mins
A delightful combination of browned sausage and mushrooms, fresh bread, fluffy eggs, savory cheese, and a homemade mushroom gravy, creating this incredibly delicious and satisfying make-ahead breakfast casserole.
Pin Recipe
Ingredients
- ½ lb ground sausage
- 8 ounces button or cremini mushrooms, sliced
- 1 cup chopped onions (½ medium onion)
- 6 tablespoons butter, divided
- 2 tablespoons all-purpose flour
- 2 cups milk, divided (whole or 2%)
- 1 ½ teaspoon salt, or to taste
- About ½ teaspoon ground black pepper, to taste
- 12 large eggs
- 1 ½ cups shredded cheddar cheese
- 6 cups cubed French, artisan or other white bread (about 8 thick slices)
- Chopped fresh chives, for garnish (optional)
Instructions
- In a large skillet set over medium high heat, cook sausage until browned and cooked all the way through. Remove from skillet and set aside.
- Add mushrooms and onions to the skillet and season with salt and pepper. Cook, stirring occasionally until softened, about 5 minutes. Remove from skillet and set aside with sausage.
- Melt 2 tablespoons of butter to the skillet and add flour. Whisk to form a thick paste and cook for about 1 minute. Add 1 cup of milk gradually to the pan while whisking constantly. Bring to a simmer, stirring until sauce is smooth and thickened. Season with 1 teaspoon salt and ¼ teaspoon pepper, or to taste. Set aside.
- Melt the remaining ¼ cup butter in a dish. Whisk the butter with the remaining 1 cup of milk and the eggs. Add ½ teaspoon of salt and ¼ teaspoon pepper.
- To assemble breakfast casserole, grease a 9×13 inch pan with butter. Spread bread cubes into an even layer in the pan. Carefully pour egg mixture over the bread cubes, making sure all the bread is moistened. Scatter sausage, mushrooms, onions, and half of the cheese on top. Finally, spoon the gravy over everything and add the rest of the cheese. Use the back of a spoon to gently push everything down into an even layer, and to make sure there are no dry pieces of bread.
- Cover with foil and chill in the fridge overnight, or at least 4 hours.
- When ready to bake, preheat oven to 350°F (175°C). Bake casserole covered for 45-60 minutes until casserole is puffed and set, taking off foil for the last 10-15 minutes.
- Top with chives if desired. Serve immediately.
Notes
- You can bake this casserole immediately after assembly, but chilling for at least 4 hours is recommended. It’s perfect for preparing the night before and baking the next morning. Great for holiday mornings and brunches!
- If desired, you can use a can of cream of mushroom soup in place of the homemade gravy in this recipe. Warm it up so it has a spreadable consistency before spooning over casserole.
Nutrition Information (per serving)
Calories: 326kcal, Carbohydrates: 16g, Protein: 16g, Fat: 22g, Saturated Fat: 11g, Polyunsaturated Fat: 2g, Monounsaturated Fat: 7g, Trans Fat: 1g, Cholesterol: 211mg, Sodium: 644mg, Potassium: 285mg, Fiber: 1g, Sugar: 4g, Vitamin A: 635IU, Vitamin C: 2mg, Calcium: 239mg, Iron: 2mg
Cuisine: American
Course: Breakfast
Author: Annalise Sandberg
Tried this incredible recipe? I’d love to hear your thoughts! Leave a rating and review below. Don’t forget to share your creations on Instagram by tagging @completelydelicious and using the hashtag #completelydelicious.
This recipe was originally published December 2021 in partnership with Challenge Dairy, Inc. Thank you for supporting partnerships with brands I love and believe in, which make Completely Delicious possible. All opinions are always 100% my own.