This easy make-ahead breakfast casserole is a hearty, flavor-packed meal that’s perfect for feeding a crowd or prepping for the week. Loaded with sausage, veggies, bread, and cheese, it’s endlessly customizable and ideal for holidays or everyday breakfasts.

Why You’ll Love This Recipe

• Make-ahead friendly for busy mornings or special occasions
• Customizable with your favorite veggies, meats, and cheeses
• Feeds a crowd with one pan
• Delicious reheated for leftovers
• Can be made with bread or potatoes for the base

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

• 4 cups (175g or 6 oz) crusty bread, cubed
• 1 teaspoon olive oil
• 1 pound ground pork sausage, casings removed
• 1 teaspoon dried rosemary or Italian seasoning (optional)
• 3/4 cup (100g) chopped yellow onion
• 2 garlic cloves, minced
• 2 cups (275g) chopped bell peppers
• 1 cup (100g) sliced mushrooms
• 1 cup fresh spinach, roughly chopped
• 12 large eggs
• 1/4 teaspoon salt
• 1/8 teaspoon freshly ground black pepper
• 2/3 cup (160ml) milk or half-and-half
• 1 cup (100g) shredded cheddar cheese
• Optional garnish: chopped parsley or green onion

Directions

1. Preheat oven to 375°F (191°C). Grease a 9×13-inch or 3–4-quart oven-safe dish.
2. Arrange cubed bread evenly in the bottom of the dish.
3. Heat olive oil in a large skillet over medium heat. Add sausage and seasoning. Break into small pieces as it cooks.
4. Add onion, garlic, bell peppers, mushrooms, and spinach. Cook until softened and sausage is mostly cooked, about 5–6 minutes.
5. Spread sausage and vegetable mixture evenly over the bread.
6. In a mixing bowl, whisk eggs, salt, pepper, milk, and cheese. Pour evenly over the sausage/veggie layer.
7. Cover and refrigerate for at least 30 minutes or up to 24 hours.
8. When ready to bake, let it sit at room temperature for 10–15 minutes. Bake uncovered for 40–45 minutes, until golden on top and center is set.
9. Cool for 10 minutes before slicing and serving.

Servings and timing

• Servings: 12
• Prep time: 20 minutes
• Cook time: 45 minutes
• Total time: 1 hour 30 minutes

Variations

• Potato base: Substitute 3 cups frozen hash browns for the bread.
• Vegetarian: Omit sausage and add another cup of veggies.
• Meat options: Use bacon, ham, turkey sausage, or ground chicken.
• Cheese swaps: Try pepper jack, gouda, feta, or Swiss.
• Add spice: Include jalapeños or hot sauce in the egg mixture.

Storage/Reheating

• Store leftovers in the refrigerator for up to 5 days.
• Reheat individual portions in the microwave or oven.
• To freeze: Assemble and freeze unbaked or freeze baked casserole after cooling. Thaw overnight before reheating at 350°F.

FAQs

Can I make this casserole without bread?

Yes, substitute with frozen or cooked diced potatoes.

Can I make this ahead of time?

Absolutely, it can be assembled up to 24 hours in advance.

Can I freeze this casserole?

Yes, freeze either baked or unbaked for up to 3 months.

How do I avoid a soggy casserole?

Use crusty or slightly stale bread and allow it time to soak in the egg mixture.

Can I use egg whites only?

Yes, replace whole eggs with egg whites or a mix to lighten the dish.

What if I don’t have sausage?

Use any ground meat, chopped bacon, or pre-cooked ham.

Can I add more vegetables?

Yes, just keep total volume around 3–4 cups.

Can I bake this in a different size pan?

Yes, adjust for deeper or smaller pans and increase bake time if needed.

What milk works best?

Whole milk or half-and-half gives the richest texture, but low-fat or non-dairy options also work.

Can I serve this for dinner?

Absolutely. It’s hearty enough for a satisfying evening meal.

Conclusion

This easy make-ahead breakfast casserole brings flavor, convenience, and versatility to your kitchen. Whether you’re hosting a brunch or need a go-to breakfast for the week, this reliable recipe will serve you well. Mix, bake, and enjoy!

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