Introduction

The Ultimate Overnight Breakfast Casserole is a comforting, make-ahead dish perfect for busy mornings or weekend brunches. Packed with hearty bread, eggs, cheese, and your choice of meat and vegetables, it offers a custardy texture and rich flavors that everyone will love.

The image shows a close-up of a thick, square breakfast casserole with about five visible layers. The bottom layer is a light yellow scrambled egg base mixed with small pieces of cooked sausage, followed by a creamy white layer that looks like melted cheese or a cheese and egg mix. Above that, there's another layer of fluffy yellow eggs combined with browned sausage chunks. The top layer is golden brown melted cheese with some crispy dark brown spots from baking, sprinkled with chopped green onions adding a fresh green color. The casserole sits in a white rectangular baking dish on a white marbled surface with a few extra green onion pieces scattered around. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

6 cups sturdy bread cubes (sourdough or whole grain recommended; gluten-free if preferred)
8 large fresh eggs
2 cups whole milk (or almond/oat milk for dairy-free)
2 cups shredded cheddar cheese (or mozzarella/vegan cheese alternative)
1 pound ground meat (ground beef, turkey, or plant-based sausage; tofu for vegetarian)
1 cup chopped bell peppers
1 cup chopped onions
1 cup fresh spinach (or substitute with zucchini, mushrooms, or other vegetables)
Salt and pepper to taste
Optional seasonings: garlic powder, paprika

Instructions

Step 1: Cut the bread into cubes. Leave them out overnight to dry or toast lightly in the oven for a few minutes.
Step 2: In a skillet over medium heat, cook the ground meat until browned. Drain excess fat and set aside.
Step 3: In the same skillet, heat a bit of oil and sauté chopped onions and bell peppers until soft. Add spinach last and cook until wilted.
Step 4: In a large bowl, whisk together eggs, milk, salt, pepper, and any desired seasonings like garlic powder or paprika.
Step 5: In a large baking dish, layer the bread cubes, then the cooked meat, sautéed vegetables, and shredded cheese. Pour the egg mixture evenly over everything.
Step 6: Cover the dish with plastic wrap and refrigerate overnight to allow the bread to soak up the egg mixture.
Step 7: The next morning, preheat your oven to 350°F (175°C). Remove the plastic wrap and bake the casserole for 45-55 minutes until set and golden on top.
Step 8: Let the casserole cool for a few minutes before slicing. Serve warm and enjoy!

Tips & Variations

Use day-old bread or toast the cubes to prevent sogginess.
Substitute veggies based on seasonal availability or personal preference.
For a vegan version, replace eggs with aquafaba or commercial egg replacer and use plant-based cheese and meat alternatives.
Add herbs like chives or parsley for extra freshness.
Make it spicier by adding diced jalapeños or a pinch of cayenne pepper.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. To reheat, warm individual portions in the microwave or oven until heated through. This casserole can also be frozen for up to 1 month; thaw overnight in the fridge and reheat before serving.

How to Serve

The image shows a thick square slice of a breakfast casserole on a white plate, placed on a white marbled surface. The dish has three visible layers: the bottom and middle layers are filled with cooked ground sausage, mixed with fluffy, light yellow scrambled eggs that have a soft texture; between these layers there is a layer of white melted cheese that looks creamy and smooth. The top layer is a golden-brown melted cheese crust, with browned spots and chunks of sausage, sprinkled with small, bright green chopped scallions. The casserole looks rich, with a slightly crispy top and soft, dense layers underneath. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare this casserole without meat?

Yes, simply omit the meat and add extra vegetables or tofu to keep it hearty and flavorful.

How do I make this casserole dairy-free?

Use plant-based milk like almond or oat, and choose a vegan cheese alternative or omit the cheese altogether for a dairy-free version.

Ultimate Overnight Breakfast Casserole Recipe

Print Recipe

★★★★★

4.9 from 111 reviews

The Ultimate Overnight Breakfast Casserole is a hearty and delicious make-ahead dish perfect for busy mornings. Featuring layers of sturdy bread, cooked meat, sautéed vegetables, and melty cheese soaked in a rich egg and milk custard, this casserole is refrigerated overnight and baked until golden and set. It’s versatile, allowing substitutions for bread, milk, cheese, meat, and vegetables to accommodate dietary preferences and needs.

Author: zara
Prep Time: 20 minutes
Cook Time: 50 minutes
Total Time: 12 hours 10 minutes
Yield: 8 servings 1x
Category: Breakfast Casserole
Method: Baking
Cuisine: American

Ingredients

Scale

Bread

6 cups sturdy bread cubes (sourdough or whole grain; gluten-free bread for substitution)

Egg Mixture

8 large fresh eggs
2 cups whole milk (or almond milk/oat milk for dairy-free)
1 teaspoon salt
1/2 teaspoon black pepper
Optional seasonings: 1/2 teaspoon garlic powder, 1/2 teaspoon paprika

Meat

1 pound ground beef (or ground turkey; tofu or plant-based sausage for vegetarian)

Vegetables

1 medium onion, chopped
1 bell pepper, chopped
2 cups fresh spinach (or substitute zucchini or mushrooms)
1 tablespoon olive oil or vegetable oil

Cheese

1 1/2 cups shredded cheddar cheese (or mozzarella or vegan cheese alternative)

Instructions

Prepare the Bread: Cut your chosen bread into cubes. You can leave the cubes out overnight to dry slightly or lightly toast them in the oven for a few minutes to enhance texture and flavor.
Cook the Meat: Heat a skillet over medium heat and cook the ground beef (or meat substitute) until browned and cooked through. Drain any excess fat and set the meat aside.
Sauté the Vegetables: In the same skillet, add a tablespoon of oil. Sauté chopped onions and bell peppers until they soften, about 5-7 minutes. Add spinach last and cook just until wilted, then remove from heat.
Mix the Egg Mixture: In a large bowl, whisk together eggs, milk, salt, pepper, and any optional seasonings such as garlic powder and paprika until fully combined and smooth.
Combine Ingredients: In a large baking dish, evenly layer the bread cubes first. Top with the cooked meat, followed by the sautéed vegetables, and then sprinkle the shredded cheese over everything. Pour the prepared egg mixture evenly over the layers to soak the bread and fillings.
Refrigerate Overnight: Cover the baking dish tightly with plastic wrap and refrigerate it overnight, allowing the bread to absorb the egg custard for a creamy consistency.
Bake: The next morning, preheat the oven to 350°F (175°C). Remove the plastic wrap and bake the casserole uncovered for 45 to 55 minutes, or until the casserole is fully set and the top is golden and slightly crispy.
Serve: Let the casserole cool for 5-10 minutes after baking. Slice into portions and serve warm for a satisfying breakfast.

Notes

You can customize the casserole by using different types of bread or dairy-free milk alternatives to suit your taste and dietary preferences.
For a vegetarian version, replace the meat with crumbled firm tofu or a plant-based sausage alternative.
Feel free to swap or add vegetables based on what’s available, like mushrooms, zucchini, or kale.
Letting the dish rest after baking helps it hold together better when sliced.
Use fresh eggs for best texture and flavor; aquafaba or commercial egg replacer can be used as substitutes for those avoiding eggs.
To enhance crispiness, you can sprinkle extra cheese on top halfway through baking.

Keywords: overnight breakfast casserole, breakfast bake, make-ahead breakfast, egg casserole, savory breakfast, baked breakfast casserole