Sausage and Mushroom Breakfast Casserole
Sausage and mushrooms, bread, eggs, cheese and homemade mushroom gravy come together in this delicious make-ahead breakfast casserole. It’s perfect for holidays, brunches and other special occasions!
Growing up, we always headed to my grandparents house for breakfast on Christmas morning after opening our presents. And for as long as I can remember, my grandma always had this sausage and mushroom breakfast casserole hot and ready for us.
I’ve recreated her recipe with a few updates, but it’s just as delicious and satisfying as I remember. It’s the perfect savory make-ahead breakfast dish for special occasions!
Table of Contents
- You'll love this make-ahead breakfast casserole
- Ingredients you'll need
- How to make sausage and mushroom breakfast casserole
- Recipe tips
- Serving suggestions
- More make-ahead breakfast ideas
- Get the recipe
You’ll love this make-ahead breakfast casserole
You’ll love the combination of flavors in this savory breakfast casserole. Sausage, mushrooms, onions, and cheese— yum!
But what makes this dish really special is the creamy mushroom gravy that you spoon over the top. It helps the casserole stay moist and gives the dish so much great flavor. My grandma used a can of cream of mushroom soup, but I’ve made mine from scratch. And you can use either option!
Like many breakfast casseroles, it can be assembled the night before and baked fresh in the morning. So you can have a tasty homemade breakfast without any effort the morning of! Perfect for Christmas, Thanksgiving or other holidays.
“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.” — reader KJT
Ingredients you’ll need
Here’s everything you need to make this sausage and mushroom breakfast casserole (find the full recipe in the recipe card below):
- Butter
- Ground breakfast sausage
- Button, cremini or baby bella mushrooms
- Onion
- Cheddar cheese
- Eggs
- French bread or other other loaf of white bread
- Milk, preferably whole milk or 2%
- All-purpose flour
- Salt and pepper
- Fresh chives, for an optional garnish
How to make sausage and mushroom breakfast casserole
- Brown sausage, mushrooms and onions. Brown sausage in a skillet first until cooked through, then set aside while you cook mushrooms and onions in butter.
- Make gravy. In the same skillet, whisk together melted butter and flour to make a “roux”. Cook for about 1 minute, then add milk gradually while whisking constantly. Simmer until thickened, then season with salt and pepper.
- Assemble casserole. Spread bread cubes into an even layer in a greased 9×13-inch casserole dish. Whisk together eggs, milk, and melted butter and pour over the bread cubes. Scatter sausage, mushrooms, onions, and half of the cheese on top. Finally, spoon the gravy over everything and add the rest of the cheese.
- Chill for 4 hours or overnight. Cover the casserole dish with foil and chill for at least 4 hours in the fridge.
- Bake. Preheat oven to 350°F and bake casserole for 45-60 minutes until casserole is puffed and completely set in the middle, removing the foil for the last 10-15 minutes of baking. If desired, sprinkle with fresh chives after baking.
- Serve! Slice and serve while it’s hot. Enjoy!
Recipe tips
- How to make this breakfast casserole ahead of time: You can bake this casserole immediately after assembling, but I recommend chilling it for at least 4 hours so the bread has time to soak up the egg mixture. It’s perfect for making the night before, and can be stored in the fridge for up to 24 hours before baking. When ready to bake, simply pop it straight from the fridge into the oven.
- Use a can of cream of mushroom soup if you want! If you’d like to skip the homemade gravy step and make it the old-fashioned way my grandma did, you can use a can of cream of mushroom soup instead. Warm it up so it has a more spreadable consistency, then spoon it over the casserole in place of the gravy.
- Flavor variations: Breakfast casseroles are very adaptable! Feel free to use a different variety of cheese, leave out the sausage for a vegetarian option or use turkey or chicken sausage instead, or add other vegetables like spinach or bell peppers. Don’t like mushrooms? Simply leave them out!
- How to know when it’s done: You’ll know the breakfast casserole is done when there are no jiggly bits of filling in the center. Gently shake the dish and if it’s completely set, it’s ready!
- How to reheat breakfast casserole: This sausage and mushroom breakfast casserole also reheats well after it’s been baked. Warm the entire dish, covered, in a 300°F oven for about 30 minutes. You can also enjoy leftover slices reheated in the microwave.
Serving suggestions
Looking for a few sides to serve alongside this breakfast casserole? If you’re serving a larger crowd, or if it’s for a special occasion, here are a few recommendations:
Get the recipe
Sausage and Mushroom Breakfast Casserole
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 and onions evenly in the pan. Top with half of the cheese.
- Spoon sauce over the casserole in heavy drizzles so there will be pockets of sauce among the other ingredients. Top with 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. 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.
Video
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.
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.
This was really good and I will make it again. I added spinach to up the veggie content, and that was yummo. I did put the full two cups of milk into the eggs, and was worried I had messed it up, but it was not overly “soggy” in any way, so that was a win. I also added some beef bullion to the gravy to give it more flavor since there wasn’t really much mushroom jus in the bottom of the pan.
The only thing I’ll change in the future is I’ll add more seasoning. I’m thinking the kind of seasoning in the stuffing you make at thanksgiving, so like, sage and such.
Overall, this is a great dish for a group, but I made it just so my husband and I don’t have to worry about breakfast throughout the week. Thanks for sharing!
It’s excellent!! I used turkey sausage and some extra mushrooms
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.
I had some leftover cooked mushrooms, so I used those. And Turkey Kielbase instead of regular sausage. I sprinkled a small amount of uncooked diced onion over the egg mixture and bread before layering on the kielbase and cheese – that really worked!
Next time, though, to save time, I will try using the soup instead of making the gravy. I think it will be just as good.