Cheesy Sausage Breakfast Casserole

Cheesy Sausage Breakfast Casserole is the ultimate way to start your morning with warmth and flavor. Packed with fluffy eggs, savory sausage, sautéed vegetables, and two kinds of melty cheese, this comforting dish is everything you love about breakfast in one hearty bite. Even better, it can be made ahead, making busy mornings a whole lot easier.

This casserole brings together the classic charm of homestyle cooking with a modern twist. The sausage adds richness, the colorful peppers and spinach provide freshness, and the cheese creates a luscious, gooey finish. Because it bakes beautifully in just one dish, cleanup is minimal, which makes it a favorite for both weekday mornings and weekend brunch gatherings.

Interestingly, breakfast casseroles became popular in the mid-20th century as a practical way to feed large families or church potlucks. Today, they remain a timeless staple, loved for their versatility and ability to bring people together around the table.

Serve Cheesy Sausage Breakfast Casserole warm, slice by slice, and watch it disappear quickly!

Recipe Yield: 8 servings

INGREDIENTS

1 lb breakfast sausage, casing removed
12 large eggs
2 cups shredded sharp cheddar cheese, divided
1 cup shredded mozzarella cheese
1 red bell pepper, diced
1 green bell pepper, diced
1 small yellow onion, diced
2 cups baby spinach, chopped
1 cup whole milk
1 tsp garlic powder
1 tsp smoked paprika
1 tsp salt
½ tsp black pepper
2 tbsp fresh parsley, chopped

INSTRUCTIONS

1. Cook the sausage:
Heat a large skillet over medium heat. Cook sausage for 6–7 minutes, breaking it apart, until browned and fully cooked. Transfer to a plate.

2. Sauté the vegetables:
In the same skillet, add bell peppers and onion. Cook for 4–5 minutes until softened. Stir in spinach and cook for 1 minute until wilted. Remove from heat.

3. Whisk the eggs:
In a large mixing bowl, whisk together eggs, milk, garlic powder, smoked paprika, salt, and black pepper until smooth and well combined.

4. Assemble the casserole:
Grease a 9×13-inch baking dish. Spread sausage evenly across the bottom, then layer sautéed vegetables. Sprinkle with 1½ cups cheddar and 1 cup mozzarella. Pour egg mixture over the top. Gently shake the dish to settle the mixture.

5. Bake the casserole:
Preheat oven to 375°F (190°C). Bake uncovered for 35–40 minutes until eggs are set in the center, the top is golden brown, and the internal temperature reaches 160°F (71°C).

6. Garnish and serve:
Remove from oven, sprinkle with remaining ½ cup cheddar, and let rest for 5 minutes. Garnish with fresh parsley before slicing and serving warm.

Helpful Tips to Perfect This Recipe

• Prep Ahead for Easy Mornings: Assemble the casserole the night before, cover tightly, and refrigerate. In the morning, bake as directed for a stress-free breakfast.
• Cheese Choices Matter: Combining cheddar with mozzarella creates a gooey, flavorful bite. For extra sharpness, try adding Gruyère or Monterey Jack.
• Veggie Customization: This casserole works well with mushrooms, zucchini, or even roasted tomatoes. Just be sure to sauté or roast vegetables first to avoid excess moisture.