This Sausage, Cheese and Veggie Breakfast Casserole is made with Italian chicken sausage, sautéed broccoli, mushrooms, roasted peppers, and mozzarella cheese for an Italian-inspired spin on a brunch favorite.
Make-Ahead Breakfast Casserole Recipe
If you like your breakfasts on the savory side, this hearty Breakfast Casserole with Sausage, Cheese, and Veggies is for you! I love that it has just the right mix of veggies, Italian sausage, and mozzarella in every bite. As with most healthy breakfast casserole recipes, eggs bind it all together; I add extra egg whites to make this breakfast casserole a little extra fluffy (and boost the protein too). Whether you’re hosting brunch, prepping breakfast for the week, or need a prep-ahead meal for a holiday morning with your family, this recipe delivers!
Why This Breakfast Casserole Is the Perfect Brunch Dish
I love the convenience of making a large breakfast casserole when I have friends and family over for breakfast or brunch. It’s also great for meal prep since you can make it ahead and heat it up during the week. You can use any combination of vegetables to make this casserole, but I love how the broccoli and roasted peppers mimic the festive Christmas colors. This would also go great with Crispy Hash Browns!
- Great for making ahead: This is the kind of overnight breakfast casserole you can assemble the night before and bake in the morning.
- So much flavor: Some breakfast casseroles are just pork sausage, cheese, and eggs, but I wanted something with more flavor to it! The veggies and Italian sausage really take this brunch classic to the next level.
- High-protein and super satisfying: Sausage, eggs, and cheese add protein, the veggies are high in fiber, and it all comes together for a filling breakfast to power you through your day.
- Adaptable: Swap the veggies for what’s in your fridge, change the cheese, or use turkey sausage—this recipe will work as long as you keep the ingredient ratios the same.
For another breakfast casserole to add to your brunch menu, try my Bacon Spinach Breakfast Casserole with Gruyère Cheese!
Sausage, Cheese and Veggie Breakfast Casserole
Ingredients
- 7 oz 2 links sweet Italian chicken sausage, removed from skin
- olive oil spray
- 1 3/4 cups part skim mozzarella, shredded (for gf, check labels)
- 1 tbsp olive oil
- 1/3 cup chopped shallots
- 5 oz sliced shiitake mushrooms
- 1 cup chopped roasted red bell peppers, from a 12 oz jar
- 1 1/2 cups finely chopped broccoli florets
- 8 large whole eggs
- 4 large egg whites
- 1/4 cup fat free milk
- 2 tbsp grated parmesan cheese
- 1/2 tsp kosher salt
- 1/4 tsp ground black pepper
Instructions
- Preheat the oven to 375°F. Spray a 9 x 13 baking dish with oil. Place half of cheese into the baking dish.
- Spray a large nonstick skillet with cooking spray, cook the sausage over medium heat breaking up as it cooks until browned and cooked through. Set aside.
- Add the oil to the skillet with the shallots and mushrooms and saute until vegetables are tender, about 5 to 6 minutes. Add the roasted peppers, broccoli and return the sausage, cook 1 minute; mix well and remove from heat. Spread evenly over the cheese mixture.
- In a large bowl combine the eggs, egg whites, milk, parmesan, salt and pepper and whisk well. Slowly pour over the vegetables in the baking dish and top with remaining cheese.
- Bake until a knife inserted near the center comes out clean, 32 to 35 minutes. Let stand 8 to 10 minutes before cutting into 8 pieces.
Last Step:
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Ingredients You’ll Need
Here are some notes on the ingredients for this breakfast casserole. See exact measurements in the recipe card above.
- Sweet Italian chicken sausage isn’t a typical choice for a breakfast casserole and that’s why I love it here. It’s so much more delicious than breakfast sausage.
- Olive oil spray, for browning the sausage without adding a lot of oil.
- Part-skim mozzarella adds layers of melty goodness.
- Olive oil for cooking the vegetables.
- Shallots for an onion flavor that’s mild and slightly sweet.
- Shiitake mushrooms or any sliced mushrooms you like.
- Roasted red bell peppers add a nice sweetness. You could roast your own, but I find buying them in a jar much easier when I’m prepping for a brunch or holiday.
- Broccoli florets – I use fresh, which have a better texture in the casserole than frozen.
- Eggs – You’ll need a combination of whole eggs, along with some egg whites.
- Fat-free milk to beat with the eggs for a savory custard, which bakes up light and fluffy. A higher fat milk is fine too, but the nutritional information will change.
- Parmesan cheese – A complement to the mild mozzarella; Parmesan is less melty, but it has a more pronounced flavor.
- Kosher salt and black pepper, for seasoning.
How to Make Breakfast Casserole
These step-by-step photos will show you the process of making this breakfast casserole recipe. See the recipe card at the bottom for printable directions.
- Prepare: Preheat your oven to 375°F and spray a 9×13 baking dish with oil. Add half of the mozzarella to the dish.
- Brown the sausage: Coat a skillet with cooking spray and brown the sausage, breaking it up as it cooks. Transfer to a plate or bowl.
- Sauté the veggies: Cook the shallots and mushrooms with the olive oil in the skillet until tender, then add the peppers, broccoli, and sausage. Cook for a minute and remove from heat.
- Transfer the veggies to the casserole dish: Spread the veggie-sausage mixture over the cheese.
- Mix the eggs: Whisk the eggs, egg whites, milk, Parmesan, salt, and pepper in a large bowl until smooth. Pour this over vegetables.
- Bake: Top with the remaining mozzarella and bake for 32 to 35 minutes, or until a knife inserted near the center comes out clean. Rest for 8 to 10 minutes before slicing and serving.
Helpful Tips
- Meal prep it: You can prep all the ingredients ahead, cook the sausage and veggies and assemble the rest in the morning, or assemble the whole casserole the night before.
- Make it your own: If you hate mushrooms, or cheese, or maybe even sausage, you can use whatever you want here! Swap mozzarella for Swiss cheese, Feta, cheddar or leave it out. Swap mushrooms for asparagus, or swap sausage for ham. There are no rules, use what YOU like.
- Don’t use all egg whites: I personally prefer to use whole eggs with a few egg whites to lighten it up a bit but you can use the whole egg if you prefer. Too many egg whites gives it a spongy texture, so finding the right balance of whole eggs to egg whites is crucial, plus the yolk is good for you so don’t forget that!
Serving Suggestions
If I’m having this for a weekday meal prep breakfast, I usually just serve it with some fresh fruit on the side. But when I’m making this breakfast casserole for a crowd, I pair it with:
Easy Breakfast Sides
These breakfast side dishes are perfect for when you’re hosting a brunch.
Proper Storage
- Refrigerator: Store slices of this breakfast casserole in an airtight container for 4–5 days.
- Freezer: Cut the leftovers in portions and freeze them in freezer safe containers. This way whenever you need breakfast in a hurry, you can reheat them and know exactly what the portions are.
- To reheat: Thaw the night before (if you’ve frozen it) and heat it up in the microwave or oven at 350°F until warmed through.
