Overnight Breakfast Casserole features bites of hearty bread, sausage, veggies and cheese all nestled into the very best creamy seasoned egg mixture! It’s the best make ahead recipe that’s easy to assemble and even easier to serve to a crowd. Use this low stress recipe to make your mornings delicious!

A serving of breakfast casserole is plated next to a whole dish.

Overnight Breakfast Casserole

Allow me to paint the picture for you that I myself have envisioned all too many times. It’s Christmas morning and you’ve made everything perfect – Santa has delivered the perfect gifts, the fireplace is crackling at the perfect temperature, and everyone has the most perfect matching pajamas. But there’s an issue… everyone is hungry and you don’t have a breakfast plan.

If you’ve also found yourself in this position, I’m here to change the game forever! This overnight breakfast casserole is a lifesaver not just on Christmas morning, but any time you have a big morning with family and/or friends. It’s great for feeding a small army and it’s nice and low stress so you don’t have to work too hard first thing in the morning.

You pretty much just have to toss everything into a baking dish, cover it, and let it hang out in the fridge overnight. In the morning, you bake it for about 40 minutes and voila! Breakfast is served, and it is so good. Cheeses, veggies, sausage and boldly seasoned eggs come together in the best medley of flavors and textures that’ll keep you full after just one protein-packed serving.

A casserole dish is filled with baked breakfast casserole.

How to Make Overnight Breakfast Casserole

Take a quick look at how easy it is to make this breakfast casserole! For more details, scroll down to the recipe card.

  1. Add the first layer. Spray a casserole dish with cooking spray. Then, add the bread cubes in a single layer on the bottom and cover them with half of the cheddar cheese.
  2. Cook the sausage. Heat a skillet over medium heat. Add the sausage to the pan and break it up as it cooks into smaller bite sized pieces. Cook until it’s fully browned. Use a slotted spoon to transfer it to a bowl. Reserve about 1 TBSP of fat in the skillet.
  3. Sauté the veggies. Add the chopped onions to the pan and cook until softened. Stir in the peppers, mushrooms, garlic and fresh spinach. Keep cooking until everything starts to soften. Mix in the Italian seasoning.
  4. Add the sausage. Toss the sausage back into the pan and remove it from the heat.
  5. Assemble the casserole. Spread the sausage and veggies all over the cheesy bread. In a different bowl, whisk together the eggs with all of the seasonings and half and half. Pour this mixture all over the casserole in an even layer.
  6. Refrigerate. Wrap the dish with plastic wrap and let it chill in the fridge for at least 30 minutes and up to 24 hours. Like I said, great make ahead recipe!
  7. Bake. Let the casserole adjust to room temperature for 30 minutes prior to baking. Then, bake uncovered at 375°F for 40-45 minutes or until golden brown and cooked all the way through.
  8. Rest and garnish. Rest for about 15 minutes at room temperature prior to garnishing with parmesan, green onions and fresh parsley.
Forks are placed next to a single serving of casserole.

Make it Vegetarian

Just omit the sausage entirely or replace it with a plant based alternative.

How long can overnight breakfast casserole sit in the fridge?

This can be prepared and placed in the fridge, unbaked, for up to 24 hours. Just make sure it’s covered tightly with plastic wrap.

What kind of bread works best?

Use a hearty, sturdy bakery bread like challah, sourdough or Italian. Remember to remove the crust! Also, note that you can omit the bread if you’d like this recipe to be low carb.

A slice of breakfast casserole is garnished with green onions.

Check out more of the best easy breakfast recipes!

For more easy breakfast recipes, follow us on instagram and Facebook!

A slice of breakfast casserole is garnished with green onions.

Get the Recipe: Overnight Breakfast Casserole Recipe

Overnight Breakfast Casserole is the best way to start the day. Make the casserole the day before and let it chill out until you're ready to bake it. Mix it up with whatever you have in the fridge, this casserole is never the same twice.
5 from 1 vote


  • 2 cups hearty bread cut into 1 inch cubes, crust removed
  • 1 cup shredded cheddar cheese
  • 1 cup shredded Colby Jack or Pepper Jack cheese
  • 1 pound bulk sausage or sausage with casings removed
  • 1 large onion, diced
  • 1 red bell pepper, diced
  • 1 orange bell pepper, diced
  • 8 ounces sliced mushrooms
  • 2 garlic cloves, minced
  • 2 cups baby spinach, chopped
  • 1 tablespoon Italian seasoning
  • 12 large eggs
  • 1/2 tablespoon garlic powder
  • 1/2 teaspoon onion powder
  • 1/4 teaspoon kosher salt
  • 1/4 teaspoon freshly ground pepper
  • 1 cup half and half
  • Grated Parmesan cheese, Green onion and parsley for garnish, optional


  • 1 baking dish


  • Coat a 9×13 baking dish with cooking spray.
  • Arrange the bread cubes in an even layer on the bottom of the dish.
  • Sprinkle half the cheddar cheese over the bread and reserve the remaining cheese for later.
  • Heat a large skillet over medium heat. Add the sausage to the pan and break up into bite sized pieces with a fork or spatula as it cooks. Cook the sausage until no longer pink. Transfer to a bowl with a slotted spoon and drain off all but 1 tablespoon of fat.
  • Add the onion to the pan and cook until beginning to soften. Stir in the bell peppers, mushrooms, garlic and spinach. Continue to cook until beginning to soften.
  • Add the Italian seasoning and cook for 1 minute.
  • Add the sausage back to the pan and remove from the heat.
  • Spread the sausage mixture evenly over the bread and cheese.
  • Whisk together the eggs, garlic powder, onion powder, salt, pepper and half and half.
  • Pour the egg mixture over the casserole in an even layer.
  • Cover with plastic wrap and refrigerate for no less than 30 minutes and up to 24 hours.
  • When ready to bake, remove the casserole from the refrigerator, top with the remaining cheese and rest at room temperature for 30 minutes.
  • Preheat the oven to 375˚F.
  • Bake the casserole, uncovered, for 40-45 minutes or until golden brown, puffed up and the center is cooked through. (You can test it with a toothpick, if it comes out clean, it’s fine.)
  • Allow to rest at room temperature for 15 minutes.
  • Sprinkle with parmesan cheese, green onion and parsley, if using.
  • Serve hot or room temperature.


Breakfast casserole can be made up to 48 hours in advance. At the very least, your casserole should chill for 1 hour to allow the ingredients to absorb into the bread.
Calories: 403kcal, Carbohydrates: 24g, Protein: 22g, Fat: 25g, Saturated Fat: 10g, Polyunsaturated Fat: 3g, Monounsaturated Fat: 9g, Trans Fat: 0.1g, Cholesterol: 216mg, Sodium: 675mg, Potassium: 407mg, Fiber: 3g, Sugar: 5g, Vitamin A: 1602IU, Vitamin C: 29mg, Calcium: 253mg, Iron: 3mg