Easy Breakfast Casserole

This easy breakfast casserole is adaptable to whatever ingredients you have on hand—cheese, veggies, meats—and can be assembled the night before and baked in the morning. Or eaten for dinner—your choice!

By
Elise Bauer
Elise Bauer
Elise Bauer
Elise founded Simply Recipes in 2003 and led the site until 2019. She has an MA in Food Research from Stanford University.
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Updated March 10, 2022
Elise Bauer
Side shot of finished breakfast casserole in a glass baking pan
Elise Bauer

On vacation, having too much fun to realize that nothing has been planned for meals, fridge mostly empty, remembering that uh-oh, I'm the one in charge of feeding my friend's children that day.

Oops!

Open the refrigerator door, see half a dozen eggs, half a carton of milk, some cheddar cheese, leftover sausage from biscuits and gravy the day before, a little broccoli, a leftover ear of corn (cooked).

Open the freezer and see half a loaf of sliced bread. Saved!

Whew. I won't have to reach for the boxed mac and cheese.

Video: How to Make Easy Breakfast Casserole

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Easy Breakfast Casserole

What Is a Breakfast Casserole?

Have you ever made a breakfast casserole?

The basic ingredients are eggs, cheese, milk, and bread. It's the easiest thing in the world to put together. We have a sausage breakfast casserole on the site that is one of my favorites.

The great thing about a breakfast casserole is that you can add almost anything you want to the base. Italian sausage is my all-time favorite, but bacon or ham will do, too. Or make it veggie with zucchini, broccoli, basil, and onions.

The first time I served this to the kids they insisted that it had to go on the website. The name they picked was "Open Fridge Breakfast Bake" because basically that's what I did—opened the fridge, put everything I could find into a casserole dish, and baked it.

Overhead shot of the finished breakfast casserole in a 9x13 baking dish
Elise Bauer

How to Make a Breakfast Casserole

To make a breakfast casserole you beat some eggs, add milk and cheese, add cubed bread, add "mix-ins" like mushrooms, veggies, sausage, and herbs, put it in a casserole dish and bake.

Easy, right? The ingredients basically all come together in one big casserole pan, but there are a few steps I would recommend first:

  • If you are using a lot of mushrooms, sauté them a bit beforehand to release some of their moisture.
  • You can add cooked, sturdy veggies such as broccoli into the casserole, or put them in raw. If using raw veggies, cut them into smaller pieces and know that they'll be crunchier if you put them in raw instead of cooked.
  • If you are adding sausage or bacon, cook it first before adding it to the casserole.

The proportions of ingredients are adjustable. If you add more eggs, it will result in a casserole that is more firm and less likely to deflate.

Day-old or stale bread works best for a breakfast casserole, but if you don't have any, just leave slices of fresh bread out on the counter to dry for a few hours, or put the slices in a low oven (200°F, 10 min) or toaster for a minute (just enough to dry them a little).

What to Serve With a Breakfast Casserole

Breakfast casserole is truly a meal in itself! It has starch (bread), milk, cheese, meat, and vegetables. It can be made for breakfast, lunch, or dinner.

Serve it with some sliced fresh fruit on the side for breakfast, or if making for dinner, a green salad. If you omit the veggies in the casserole, consider serving some sautéed vegetables on the side. Or if leaving out the meat, some crispy bacon or cooked sausages.

Make Ahead Instructions

Breakfast casseroles are almost designed to be made ahead. You can assemble the whole thing the night before, put it in the fridge (covered), and bake it the next morning. It's minimal work when you wake up and a low stress breakfast if you have a group of people to feed.

Slice of easy breakfast casserole on a plate
Elise Bauer

How to Keep and Reheat a Breakfast Casserole

This breakfast casserole will keep for a few days in the fridge, covered. You can microwave it until it's hot, one serving at a time, or you can reheat the whole casserole in a 350°F oven for 15 to 20 minutes until it's heated through.

Do you have a favorite breakfast casserole combo? If so, please let us know about it in the comments.

More Easy, Lazy Breakfast Casseroles

Easy Breakfast Casserole

Prep Time 15 mins
Cook Time 50 mins
Total Time 65 mins
Servings 8 servings

The ingredient proportions are estimates. The more eggs, the firmer and less likely to deflate the casserole will be.

Mushrooms tend to hold a lot of moisture, so if you use a lot of them, you may want to sauté them first to release some of their water.

Don't have day-old bread? Put slices of fresh bread into a 200°F oven for 10 minutes.

Ingredients

  • For the breakfast casserole base:
  • 6 to 10 large eggs
  • 2 to 3 cups grated cheddar cheese
  • 6 slices day-old bread, cut into 3/4-inch to 1-inch-wide cubes
  • 2 cups milk
  • Salt
  • Pepper
  • For the possible additions: 
  • 1 cup corn (cooked or frozen)
  • 1/2 cup chopped broccoli (cooked or raw, raw will turn out crunchier)
  • 1/2 cup sliced mushrooms
  • 1/4 cup sliced green onions
  • 1 cup cubed ham and/or cooked Italian sausage
  • A few slices cooked bacon, chopped
  • 1 teaspoon Herbes de Provence, or other dried herbs, (or 1 tablespoon of fresh chopped herbs such as basil, rosemary, or thyme)
  • 1/4 to 1/2 teaspoon of cumin or curry powder

Method

  1. Preheat oven to 350°F
  2. Make the casserole base:

    Beat the eggs in a large bowl. Mix in the milk and cheese.

    Add the bread and carefully stir until all pieces of bread are moistened (don't over mix or the bread may disintegrate).

    Mix the eggs and cheese for the breakfast casserole
    Elise Bauer
    mix the bread cubes into the cheese and egg mix for the egg casserole
    Elise Bauer
  3. Add the additions:

    Add salt and pepper to taste (if using Italian sausage, you won't need either). If you have a lot of additions, you might need a couple more eggs to make sure that everything is at least touching some egg mixture. Just whisk in 2 tablespoons of milk for every beaten egg you add.

    Add the add-in ingredients to the bread and egg mixture for the breakfast casserole recipe, like mushrooms, bacon, or broccoli
    Elise Bauer
    Mix all the ingredients for the egg bake together in the bowl
    Elise Bauer
  4. Bake the casserole:

    Butter a 9x13-inch casserole dish. Pour the mixture into the casserole dish. (At this point, you can bake right away or transfer the casserole to the fridge and bake it the next day.)

    Bake in a 350°F oven for 50 minutes to an hour, until the top is browned and the center springs back when touched.

    Remove from oven and let cool for 10 minutes before serving.

    Transfer the egg casserole mixture to a 9x13 baking pan
    Elise Bauer
    Bake the egg casserole until the eggs are set and the top is slightly browned
    Elise Bauer