Overnight Breakfast Casserole is the ultimate make-ahead breakfast that combines eggs, bread, cheese, and your choice of meats or vegetables into a warm, hearty, and flavorful dish. This casserole is perfect for busy mornings, holidays, or family gatherings, as you can prepare it the night before and bake it the next morning. The result is a deliciously creamy and savory breakfast casserole that’s full of flavor and makes feeding a crowd easy and stress-free.

Why You’ll Love This Recipe

Make-ahead convenience: Prepare everything the night before and bake in the morning, saving you time and stress when you’re getting ready for a busy day.
Customizable: You can easily adjust the ingredients to suit your tastes or dietary needs, adding veggies, meats, or even making it vegetarian.
Hearty and satisfying: The combination of eggs, bread, cheese, and seasonings makes for a filling breakfast that will keep you satisfied until lunchtime.
Crowd-pleaser: This casserole is great for serving a group, whether it’s a holiday brunch, a family gathering, or a breakfast for friends.

Ingredients

1 loaf of crusty bread (such as French bread or sourdough), cut into cubes
10 large eggs
2 cups milk (dairy or non-dairy)
1 teaspoon Dijon mustard (optional)
1 teaspoon garlic powder
1 teaspoon onion powder
Salt and pepper, to taste
2 cups shredded cheese (cheddar, mozzarella, or a blend)
1 cup cooked sausage (optional)
1 cup fresh spinach, mushrooms, or bell peppers (optional)
¼ cup chopped green onions or fresh parsley for garnish (optional)

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

Directions

Prepare the bread: Start by cutting the loaf of bread into cubes. If you want a crispier texture, you can lightly toast the bread cubes in the oven for 5-10 minutes at 350°F (175°C) until slightly golden.
Layer the casserole: In a greased 9×13-inch baking dish, layer the bread cubes evenly on the bottom. If you’re adding cooked sausage sprinkle it evenly over the bread. You can also add any veggies you like at this point, such as spinach, mushrooms, or bell peppers.
Make the egg mixture: In a large bowl, whisk together the eggs, milk, Dijon mustard (if using), garlic powder, onion powder, salt, and pepper. Pour the egg mixture evenly over the bread cubes and meat/veggies in the baking dish. Gently press down on the bread to make sure it absorbs the egg mixture.
Add cheese: Sprinkle the shredded cheese evenly over the top of the casserole.
Refrigerate overnight: Cover the casserole with plastic wrap or aluminum foil and refrigerate it overnight, or for at least 4-6 hours. This allows the bread to absorb the egg mixture, making the casserole more flavorful and tender.
Bake: Preheat your oven to 350°F (175°C). Once the casserole has had time to sit, remove it from the refrigerator and bake for 40-45 minutes, or until the eggs are set, and the top is golden and bubbly. If you’d like a crispier top, you can broil it for 2-3 minutes at the end.
Serve: Once baked, remove the casserole from the oven and let it cool for a few minutes before slicing. Garnish with chopped green onions or fresh parsley, if desired.

Servings and Timing

Servings: This recipe makes about 8-10 servings, depending on portion size.
Preparation time: 15 minutes (plus overnight chilling)
Baking time: 40-45 minutes
Total time: 55-60 minutes (plus chilling time)

Variations

Vegetarian version: Skip the meat and load the casserole with your favorite veggies like mushrooms, spinach, bell peppers, or zucchini.
Cheese options: Feel free to mix up the cheese. Cheddar, mozzarella, Monterey Jack, or even feta or goat cheese would work well.
Spicy kick: Add some diced jalapeños, hot sauce, or pepper jack cheese to spice things up.
Gluten-free version: Use gluten-free bread to make this casserole gluten-free.

Storage/Reheating

Storage: Store leftover casserole in an airtight container in the refrigerator for up to 3 days.
Reheating: To reheat, simply microwave individual portions for 30-60 seconds or warm the whole casserole in the oven at 350°F (175°C) for 15-20 minutes until heated through.

Overnight Breakfast Casserole Recipe

FAQs

Can I prepare this casserole in advance?

Yes, that’s the beauty of this recipe! You can prepare it the night before, refrigerate it, and bake it the next morning for a quick, easy breakfast.

Can I make this casserole without dairy?

Yes, you can use non-dairy milk (such as almond or oat milk) and dairy-free cheese to make this casserole dairy-free.

Can I use a different type of bread?

Yes, you can use any bread you like, such as sourdough, whole wheat, or even brioche. Just ensure that it’s sturdy enough to absorb the egg mixture.

Can I add potatoes to this casserole?

Yes! You can add cooked, cubed potatoes for a heartier casserole. Simply layer them with the bread and other ingredients before adding the egg mixture.

Can I freeze this casserole?

Yes, you can freeze this casserole before baking. Assemble the casserole, cover it tightly, and freeze for up to 2-3 months. When you’re ready to bake, let it thaw in the refrigerator overnight and bake as directed.

Conclusion

Overnight Breakfast Casserole is a versatile, easy-to-make dish that’s perfect for breakfast or brunch. It’s hearty, satisfying, and packed with flavors that everyone will enjoy. The best part is that it can be made ahead of time, so you can relax in the morning while the oven does the work. Whether you’re feeding a crowd or prepping breakfast for the week, this casserole is sure to become a family favorite. Enjoy the creamy, cheesy, and savory goodness with every bite!