A cheesy sausage breakfast casserole is comfort food at its best: warm, savory, and perfect for feeding a hungry crowd. It has everything you want in a morning meal—juicy sausage, fluffy eggs, soft bread, and plenty of melty cheese. It’s easy to prep ahead and pop in the oven when you’re ready.
Whether it’s a weekend brunch, a holiday morning, or a make-ahead weekday breakfast, this recipe brings big flavor with minimal fuss.
What Makes This Recipe So Good
- Hands-off cooking: Most of the work happens in the oven. Once it’s assembled, you can relax.
- Make-ahead friendly: Assemble it the night before and bake in the morning. Ideal for guests and busy mornings.
- Balanced texture: Soft custardy center, crispy edges, and gooey cheese on top.
Every bite is satisfying.
- Customizable: Swap in your favorite cheese, sausage, or veggies without complicating the process.
- Feeds a crowd: It serves 8–10 generous portions, so it’s great for gatherings.
Ingredients
- 1 pound (450 g) breakfast sausage, casings removed (mild or spicy)
- 1 tablespoon olive oil or butter (if needed)
- 1 medium yellow onion, finely chopped
- 1 red bell pepper, diced
- 8 large eggs
- 2 cups whole milk (or 1 1/2 cups milk + 1/2 cup half-and-half for richer texture)
- 1 teaspoon Dijon mustard (optional but recommended)
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- 1/2 teaspoon smoked paprika
- 1 teaspoon kosher salt, plus more to taste
- 1/2 teaspoon black pepper
- 6 cups day-old bread cubes (French bread, sourdough, or brioche), 1-inch pieces
- 2 cups shredded sharp cheddar cheese
- 1 cup shredded mozzarella or Monterey Jack
- 2 green onions, thinly sliced (for topping)
- Nonstick cooking spray or butter, for greasing the pan
Step-by-Step Instructions
- Prep the pan: Grease a 9×13-inch baking dish with cooking spray or butter. Set aside.
- Cook the sausage: In a large skillet over medium heat, cook the sausage, breaking it up with a spatula, until browned and cooked through, 6–8 minutes. If the pan is dry, add a bit of olive oil or butter.
- Sauté the veggies: Add the onion and red bell pepper to the skillet.
Cook until softened and lightly caramelized, 5–7 minutes. Season with a pinch of salt. Remove from heat and let cool slightly.
- Whisk the custard: In a large bowl, whisk together the eggs, milk, Dijon, garlic powder, onion powder, smoked paprika, salt, and pepper until smooth.
- Assemble the base: Spread the bread cubes evenly in the prepared baking dish.
Sprinkle the cooked sausage and sautéed veggies over the bread.
- Add the cheese: Scatter 1 1/2 cups cheddar and 3/4 cup mozzarella over the sausage and bread. Reserve the rest for topping.
- Pour the custard: Slowly pour the egg mixture evenly over the entire dish, pressing down lightly with the back of a spatula so the bread absorbs the liquid.
- Rest or chill: For best texture, cover and refrigerate at least 30 minutes or up to overnight. If short on time, proceed immediately.
- Bake: Preheat the oven to 350°F (175°C).
Uncover the casserole and bake for 35–45 minutes, until the center is set and the edges are golden. A knife inserted in the center should come out mostly clean.
- Finish with cheese: Sprinkle the remaining cheddar and mozzarella over the top. Bake 5–10 more minutes until melted and bubbly.
- Rest and serve: Let the casserole rest 10 minutes to set.
Garnish with green onions. Slice and enjoy.
Storage Instructions
- Refrigerator: Cool completely. Cover tightly or portion into airtight containers.
Store for up to 4 days.
- Freezer: Wrap individual slices in plastic, then foil, or place in freezer-safe containers. Freeze up to 2 months. Thaw overnight in the fridge.
- Reheat: Microwave slices for 60–90 seconds, or bake at 325°F (165°C) for 10–15 minutes until warmed through.
Add a fresh sprinkle of cheese if you like.
Health Benefits
- Protein-rich: Eggs and sausage deliver steady energy and help with satiety through the morning.
- Calcium from cheese: The cheeses provide calcium for bone health and a bit of extra protein.
- Veggie boost: Onions and bell peppers add fiber, vitamin C, and antioxidants. You can increase the vegetable content without altering the recipe structure.
- Flexible fat content: Use turkey sausage, part-skim cheese, or a mix of milk and half-and-half to tailor richness.
Pitfalls to Watch Out For
- Soggy texture: Too much milk or very soft bread can make the center mushy. Use day-old bread and measure liquids accurately.
- Undercooking: If the center jiggles significantly, it needs more time.
Tent with foil to prevent over-browning and continue baking in 5-minute increments.
- Over-salting: Sausage and cheese are salty. Taste the sausage mixture and consider reducing added salt if needed.
- Watery veggies: High-moisture vegetables (like mushrooms or spinach) should be sautéed and drained well before adding.
- Skipping the rest: Resting after baking helps the custard set and makes slicing clean and easy.
Recipe Variations
- Southwest Style: Use pepper jack, add a small can of diced green chiles, and finish with cilantro and avocado.
- Veggie-Loaded: Add sautéed mushrooms, spinach, and zucchini. Consider reducing milk by 1/4 cup to account for added moisture.
- Hash Brown Base: Swap bread for 5 cups thawed, squeezed-dry shredded hash browns.
Add 2 tablespoons melted butter for crisp edges.
- Lighter Option: Use turkey sausage, 2% milk, and part-skim mozzarella. Add extra peppers and onions for volume.
- Luxury Brunch: Mix in cooked bacon with the sausage, use gruyère in place of mozzarella, and finish with a drizzle of hot honey.
- Gluten-Free: Use gluten-free bread or the hash brown swap. Check labels on sausage and mustard to be safe.
Can I Make This Without Bread?
Yes.
Replace the bread with shredded hash browns that are thawed and patted dry. The texture will be more like a frittata with a potato base, and it bakes in roughly the same time.
Can I Prep This the Night Before?
Absolutely. Assemble, cover, and refrigerate overnight.
In the morning, uncover and bake. If the dish is very cold, add 5–10 minutes to the bake time.
What Kind of Sausage Works Best?
Breakfast pork sausage is classic. Mild or hot both work.
You can also use turkey sausage or chicken sausage; just brown it well for flavor.
How Do I Know When It’s Done?
The edges should be golden and slightly crisp, and the center should be set with only a slight wobble. A knife inserted in the center should come out mostly clean with no wet egg.
Can I Use Different Cheeses?
Yes. Cheddar adds sharpness, while mozzarella or Monterey Jack gives meltiness.
Swiss, gruyère, or Colby Jack are great alternatives. Mix two types for the best flavor and texture.
How Do I Keep the Top from Browning Too Quickly?
If the top browns before the center sets, loosely tent with foil. Remove the foil for the final 5–10 minutes, then add the last sprinkle of cheese.
In Conclusion
This cheesy sausage breakfast casserole is hearty, flexible, and easy enough for any home cook.
It’s a crowd-pleaser that welcomes swaps and add-ins, and it bakes up beautifully with minimal effort. Keep it classic or make it your own with the variations above. Either way, you’ll have a warm, cheesy breakfast that feels special without being complicated.
Ingredients
Instructions
- Prep the pan: Grease a 9x13-inch baking dish with cooking spray or butter. Set aside.
- Cook the sausage: In a large skillet over medium heat, cook the sausage, breaking it up with a spatula, until browned and cooked through, 6–8 minutes. If the pan is dry, add a bit of olive oil or butter.
- Sauté the veggies: Add the onion and red bell pepper to the skillet. Cook until softened and lightly caramelized, 5–7 minutes. Season with a pinch of salt. Remove from heat and let cool slightly.
- Whisk the custard: In a large bowl, whisk together the eggs, milk, Dijon, garlic powder, onion powder, smoked paprika, salt, and pepper until smooth.
- Assemble the base: Spread the bread cubes evenly in the prepared baking dish. Sprinkle the cooked sausage and sautéed veggies over the bread.
- Add the cheese: Scatter 1 1/2 cups cheddar and 3/4 cup mozzarella over the sausage and bread. Reserve the rest for topping.
- Pour the custard: Slowly pour the egg mixture evenly over the entire dish, pressing down lightly with the back of a spatula so the bread absorbs the liquid.
- Rest or chill: For best texture, cover and refrigerate at least 30 minutes or up to overnight. If short on time, proceed immediately.
- Bake: Preheat the oven to 350°F (175°C). Uncover the casserole and bake for 35–45 minutes, until the center is set and the edges are golden. A knife inserted in the center should come out mostly clean.
- Finish with cheese: Sprinkle the remaining cheddar and mozzarella over the top. Bake 5–10 more minutes until melted and bubbly.
- Rest and serve: Let the casserole rest 10 minutes to set. Garnish with green onions. Slice and enjoy.
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