This Easy Make-Ahead Breakfast Casserole is a game-changer for busy mornings, blending savory flavors and hearty textures in every bite. Imagine layers of fluffy eggs, crispy bacon, and melted cheese baked to golden perfection, all ready to serve in just over an hour. Perfect for feeding a crowd or meal prepping, it’s a stress-free way to start the day with something delicious and satisfying.
With only 20 minutes of prep and 45 minutes of baking, this casserole is as convenient as it is comforting. The rich, smoky aroma fills your kitchen, while the creamy eggs and crunchy toppings create a delightful contrast. Whether it’s a weekend brunch or a weekday treat, this dish promises warmth and flavor that everyone will love.
Ingredients for Easy Make-Ahead Breakfast Casserole
- 4 cups (175g or 6 oz) cubes of crusty bread (day-old bread works best)
- 1 teaspoon olive oil
- 1 pound ground pork sausage, casings removed (substitute with turkey sausage if preferred)
- 1 teaspoon dried rosemary or Italian seasoning (optional, for added flavor)
- 3/4 cup (100g) chopped yellow onion (about 1/2 of a large onion)
- 2 cloves garlic, minced
- 2 cups (275g or 9–10 oz) chopped bell peppers (use a mix of colors for vibrancy)
- 1 cup (100g or 3 oz) sliced mushrooms
- 1 cup roughly chopped fresh spinach
- 12 large eggs
- 1/4 teaspoon salt
- 1/8 teaspoon freshly ground black pepper
- 2/3 cup (160ml) milk or half-and-half (use dairy-free milk for a lactose-free option)
- 1 cup (100g or 3.5 oz) shredded cheddar cheese (substitute with your favorite cheese)
- Optional garnish: green onion and/or chopped parsley
Step-by-Step Instructions
- Prepare the dish: Grease a 9×13-inch or any 3–4-quart oven-safe dish. Arrange the bread cubes in an even layer at the bottom of the pan.
- Cook the sausage and vegetables: Heat olive oil in a large skillet over medium heat. Add the sausage and rosemary/Italian seasoning (if using). Break up the sausage into bite-size pieces as it cooks. Add the onion, garlic, bell peppers, mushrooms, and spinach. Cook until the vegetables soften slightly and the sausage is mostly cooked through, about 5–6 minutes.
- Layer the casserole: Remove the sausage and vegetable mixture from the heat and spread it evenly over the bread cubes in the dish.
- Prepare the egg mixture: In a large bowl, whisk together the eggs, salt, pepper, milk, and cheese. Pour this mixture evenly over the sausage and vegetables. Sprinkle a little extra salt and pepper on top.
- Chill: Cover the casserole with plastic wrap or aluminum foil and refrigerate for at least 30 minutes or up to 24 hours. (When ready to bake, let it sit at room temperature for 10–15 minutes while the oven preheats.)
- Bake: Preheat the oven to 375°F (191°C). Bake the casserole, uncovered, until the top is golden, the edges are crisp, and a toothpick inserted in the center comes out clean, about 40–45 minutes.
- Serve: Let the casserole cool for 10 minutes, then slice and serve. Garnish with green onions or parsley if desired.
- Store leftovers: Keep leftovers in the refrigerator for up to 5 days. Reheat in the microwave to your liking.
Serving Suggestions to Elevate Your Breakfast Casserole
Serve your Easy Make-Ahead Breakfast Casserole with a side of fresh fruit like berries or sliced bananas for a refreshing contrast. A dollop of sour cream or avocado slices can add a creamy texture, while a drizzle of hot sauce or salsa will give it a zesty kick. For a complete breakfast spread, pair it with crispy hash browns or buttery toast.
Recipe Variations to Suit Every Taste
Swap out the pork sausage for turkey sausage or even crumbled tofu for a lighter option. If you’re looking for a vegetarian twist, skip the sausage and bulk up with more veggies like zucchini or broccoli. For a cheese lover’s dream, mix in some mozzarella or Monterey Jack along with the cheddar. Don’t be afraid to get creative with your mix-ins!
Storage and Reheating Tips for Perfect Leftovers
Leftovers can be stored in an airtight container in the refrigerator for up to 5 days. To reheat, simply microwave individual portions for 1-2 minutes until warmed through. For a crispier top, reheat in the oven at 350°F (175°C) for about 10 minutes. This casserole also freezes well—wrap slices tightly in plastic wrap and aluminum foil, and freeze for up to 2 months.
Time-Saving Tips for Busy Mornings
To save time, prepare the sausage and vegetable mixture the night before and store it in the fridge. You can also cube the bread ahead of time and keep it in an airtight container. When you’re ready, just assemble the casserole and let it chill while the oven preheats. Pro tip: Use pre-shredded cheese to cut down on prep time even more!
Equipment Guidance for Hassle-Free Prep
A 9×13-inch baking dish is ideal for this recipe, but any 3–4-quart oven-safe dish will work. A whisk or fork is essential for mixing the eggs, milk, and cheese evenly. If you’re using aluminum foil to cover the casserole, make sure it’s tightly sealed to prevent any spillage in the fridge. Have a sharp knife and cutting board ready for quick veggie prep!
Easy Make-Ahead Breakfast Casserole Recipe
Ingredients
- 4 cups cubes of crusty bread
- 1 teaspoon olive oil
- 1 pound ground pork sausage, casings removed
- 1 teaspoon dried rosemary or Italian seasoning optional
- 3/4 cup chopped yellow onion 1/2 of a large onion
- 2 garlic cloves, minced
- 2 cups chopped bell peppers
- 1 cup sliced mushrooms
- 1 cup roughly chopped fresh spinach
- 12 large eggs
- 1/4 teaspoon salt
- 1/8 teaspoon freshly ground black pepper
- 2/3 cup milk or half-and-half
- 1 cup shredded cheddar cheese
- optional garnish: green onion and/or chopped parsley
Instructions
- Grease a 9×13-inch or any 3–4-quart oven-safe dish. Arrange bread cubes in an even layer in bottom of pan.
- Heat olive oil in a large skillet over medium heat. Add sausage and rosemary/Italian seasoning, if using, and break up the sausage into bite-size pieces with a wooden spoon or rubber spatula as it begins to cook. Add the onion, garlic, peppers, mushrooms, and spinach and cook until everything has slightly softened and sausage is mostly cooked through, about 5–6 minutes.
- Remove sausage and vegetable mixture from heat and spread in an even layer on top of bread.
- Whisk the eggs, salt, pepper, milk, and cheese together. Evenly pour over sausage/vegetable mixture. Add another sprinkle of salt and pepper on top.
- Cover casserole with plastic wrap or aluminum foil and refrigerate for at least 30 minutes and up to 24 hours. (When ready to bake, allow to sit at room temperature for 10–15 minutes as oven preheats.)
- Preheat the oven to 375°F (191°C). Bake the casserole, uncovered, until the top is golden, edges are crisp, and a toothpick inserted in the center comes out clean, about 40–45 minutes.
- Cool for 10 minutes, then slice and serve.
- Leftovers keep well in the refrigerator for up to 5 days. Reheat in the microwave to your liking.