This sausage breakfast casserole with hashbrowns is studded with bell peppers, onions, bread, and cheese, for an easy, delicious, and filling breakfast you can make ahead of time—perfect for company!
I’m forever a fan of meal-prepping dishes like a casserole or frittata that I can enjoy all week long. Recipes like my French toast casserole, ham and cheese breakfast casserole, and my deep dish spinach, leek, and bacon quiche are perfect for hosting a brunch crowd (and still festive enough for Christmas morning). Plus, they lend themselves well to making the night before or making the night before and baking Christmas morning (or any time). This easy breakfast casserole is teeming with savory flavor from pork breakfast sausage, peppers and onions, hashbrowns, and cheese, and it features bread, so it’s got a savory bread pudding vibe. It’s a staple in our house, and I love serving when company’s staying with us. It’s also great because you can easily swap out any of the ingredients to just use up what you have in your fridge and pantry, or to make this recipe your own.
What’s in Sausage Breakfast Casserole
You don’t need too many ingredients to make this breakfast casserole recipe, and it also lends itself well to
- Pork sausage (I use breakfast sausage)
- Onion
- Red and green bell pepper
- Kosher salt and freshly ground black pepper
- Eggs
- Milk
- Dry mustard
- Sliced white bread
- Shredded cheddar cheese
- Frozen shredded hashbrowns
How to Make Sausage Breakfast Casserole
This sausage breakfast casserole is perfect for easy breakfasts because you can prep it the night before and bake it in the morning (plus, it feeds a crowd). I love serving it for brunch, or prepping it on a Sunday night and baking it Monday morning for easy breakfasts all week long. Here’s how to make it:
Sauté the Vegetable Trinity and Sausage
- Heat a large skillet over medium-high heat and brown the sausage.
- Add the onion, red bell pepper, and green bell pepper. Season with the kosher salt and freshly ground black pepper, and cook the veggies over medium until they are soft, about 5 minutes.
- Remove the meat mixture from the pan and transfer to a large bowl or baking sheet to cool.
Whisk the Egg Mixture
- In a 1 quart measuring cup, whisk the eggs and milk until smooth.
- In a small bowl, use a fork to mix 1 tablespoon of the egg and milk mixture into the dry mustard and mix until smooth. This is the key to incorporating the mustard into the egg mixture clump-free.
- Add the mustard mixture into the quart measuring cup and mix well so that all of the mustard is incorporated. Set this aside.
How to Layer the Breakfast Casserole
- Tear the bread. First, start by tearing the bread slices into 1-inch pieces. Cover the bottom of the baking dish, fitting the pieces tightly together like puzzle pieces.
- Add the sausage and pepper mixture. Add just ¾ of the sausage and pepper mix over the bread, leaving enough for one more layer.
- Add the egg mixture. Starting at one end of the casserole, slowly pour the egg mixture over the bread and sausage mixture, evenly distributing and filling in around the casserole edges.
- Combine the hashbrowns and sausage. Toss the shredded cheese and frozen hash browns together in a bowl and add to the top of the casserole. Then, sprinkle with the rest of the sausage and pepper mixture. Tip: If making ahead of time, complete this step just before baking.
- Bake until bubbly. Bake for 60-70 minutes or until the eggs are set in the middle and bubbling at the edges. Tip: If the casserole begins to brown too much, loosely tent some aluminum foil over the top and continue to cook until the egg is set.
How to Make The Breakfast Casserole Ahead of Time
This breakfast casserole can be made the night before (this is ideal if you have company coming and don’t want to have to wake up early the next day). If making this breakfast casserole as an overnight casserole, simply add the cheese and frozen hash browns just before baking. The hashbrowns do best when cooked from frozen.
Why is my Breakfast Casserole Soggy?
You want your breakfast casserole to absorb into the bread, but it shouldn’t ever be soggy. If this happens, it’s likely due to the potatoes leaching too much water (that’s why I recommend adding the hash browns while still frozen, and also why I advise adding them just before baking).
Substitutions and Variations
The beauty of this breakfast casserole is it’s customizable. Feel free to make some ingredient swaps to use what you have on hand, or add even more ingredients if you like. Here are some tasty ideas:
- Swap out your protein. Try bacon, Canadian bacon, ham, turkey sausage, chicken sausage, or Italian sausage
- Mushrooms instead of peppers
- Add spinach
- Try croissants, challah, or a torn baguette instead of white bread
- Swiss or Fontina cheese
- Use tater tots instead of hash browns
- Add fresh herbs like thyme, rosemary, tarragon, or basil
Sausage Breakfast Casserole
Ingredients
- 1 ½ pounds pork sausage
- 1 cup chopped yellow onion
- ¾ cup chopped red bell pepper
- ¾ cup chopped green bell pepper
- 1 teaspoon kosher salt
- 1 teaspoon freshly ground black pepper
- 8 eggs
- 2 cups whole milk
- 1 tablespoon dry mustard
- 12 slices white bread
- 4 cups grated medium cheddar cheese
- 3 cups frozen shredded hash browns
Instructions
- Preheat the oven to 350°F. Spray a 9 X 13-inch casserole dish with cooking spray and set aside.
- Heat a large skillet over medium-high heat and add the sausage. Cook until the sausage is mostly browned, about 5 minutes. Add the onion, red bell pepper, and green bell pepper then season with the kosher salt and freshly ground black pepper. Turn the heat to medium and cook, stirring, until the vegetables soften, about 5 minutes. Remove the meat mixture from the pan and transfer to a large bowl or baking sheet to cool.
- In a 1 quart measuring cup, whisk the eggs and milk until smooth. In a small bowl, use a fork to mix 1 tablespoon of the egg and milk mixture into the dry mustard and mix until smooth. Add the mustard mixture into the quart measuring cup and mix well so that all of the mustard is incorporated. Set aside.
- Layer the casserole. Tear the bread slices into 1-inch pieces of bread. Cover the bottom of the baking dish, fitting the pieces tightly together like puzzle pieces. Add ¾ of the sausage and pepper mix over the bread. Starting at one end of the casserole, slowly pour the egg mixture over the bread and sausage mixture, evenly distributing and filling in around the casserole edges
- Toss the cheddar cheese and frozen hash browns together in a bowl and add to the top of the casserole. Sprinkle with the rest of the sausage mixture.
- Bake for 60-70 minutes or until the eggs are set in the middle and bubbling at the edges. If the casserole begins to brown too much, loosely tent foil over the top and continue to cook until the egg is set. Remove the casserole from the oven and let sit for about 10 minutes before cutting and serving.
