Breakfast Casserole

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Breakfast casserole with savory pieces of ham, potatoes, bell peppers, and onions, all baked into a deliciously cheesy egg custard. The ultimate Christmas morning recipe to feed a family or portion out for meal prep during the week.

For more make-ahead breakfast recipes, try my French toast casserole and delicious quiche lorraine.

Square slice of breakfast casserole on a plate with a fork.

Starting the day off with a satisfying meal is essential. This super easy breakfast casserole consists of eggs, protein, vegetables, and shredded cheese. It’s a tasty gluten-free meal that can be easily tailored to meet dietary needs. Just note that the ratio of filling to egg is key to balancing the various tastes and textures. After a few chops and stirs, watch the egg mixture transform into a big pan of savory souffle with a golden crust.

Baked egg dishes tend to have issues with becoming too rubbery or watery after cooking. This is especially the case when high-moisture vegetables or dense meats are in the mixture—sautéing the potatoes and vegetables before baking helps to dry the food and concentrate flavors. Adding cornstarch to the egg base ensures that each bite stays light and custardy while keeping the filling suspended.

Sauté the vegetables and meat

Sautéing cubes of ham, potatoes, and peppers in a cast iron skillet.

To ensure the vegetables are fully cooked before baking, each ingredient is sautéed first. The onions and garlic add aromatics, and the bell peppers add color and a slight crunch. I also use small peeled and diced Yukon gold potatoes that taste like mini hash browns for a sturdy yet creamy texture, although you can use any type of potato you like.

I use pre-cooked ham for the casserole. However, cooked breakfast sausage or bacon can be substituted. Cutting all the ingredients into smaller pieces before sautéing ensures even cooking and prevents denser elements from sinking to the bottom of the casserole.

Ingredients that help with texture

Liquid being poured into a casserole filled with vegetables, meat and cheese.

A ratio of 8 large eggs to 2 ½ cups of half and half ensures a velvety custard texture. If too many eggs are used, it can make the texture tough due to increased protein. Half and half adds a rich mouthfeel, without tasting gritty.

I use cornstarch to ensure a consistent custard-like texture throughout the casserole. It’s a nice bit of food insurance, even with the plethora of fillings threatening to break the texture of the egg base.

How long does it take to bake?

This egg breakfast casserole bakes in just 40 minutes! To check for doneness, use a toothpick inserted in the center of the pan. If it comes out dry, it’s ready. You can also gently jiggle the pan to see if the center moves. You want it to be firm.

For my science geeks, grab an instant-read thermometer and test the center of the casserole. Whole eggs start to solidify and set between 144 to 158°F (62 to 70°C). I found that between 180 to 190°F (82 to 88°C) yields the right finish, don’t overcook the casserole!

Casserole dish filled with liquid mixture and cheese.

How to reheat breakfast casserole

The glory of making this dish is that you can make it ahead of time. The easiest way to reheat the breakfast casserole is to slice it into individual portions and microwave it for about 1 minute. I got 12 generous portions in a 9 x 13-inch pan. This is an excellent method if you’re meal-prepping for the week.

The entire pan can also be reheated in a 300°F (149°C) oven until the center is warm. Guess what? You can also make all the components, cover the tray with foil and refrigerate it overnight to bake it fresh the following day. A few more minutes may be required in the oven since all the ingredients are cold. This breakfast casserole will keep for up to 5 days once baked.

Other fillings to try

This easy breakfast casserole recipe has been a game-changer in our home. It makes a large serving to feed a crowd and can be wrapped up and eaten as a quick meal solution.

Next time, I plan on switching up the fillings with sautéed mushrooms, spinach, zucchini, sweet potatoes, butternut squash, sun-dried tomatoes, Parmesan cheese, mozzarella, or feta. Just keep the amounts of similar types of ingredients and the egg mixture the same.

More breakfast recipes

Top down view of a person taking a breakfast casserole out of the oven.

Starch keeps the eggs smooth and creamy

Adding in a small amount of cornstarch keeps the consistency of the egg base tender and glossy. Cornstarch is a thickening agent that can also stabilize fully cooked eggs. The carbohydrates in the cornstarch prevent the proteins in the eggs from binding too tightly together. As the starches heat in the oven, it swells and thickens, creating a creamier mouthfeel.

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Breakfast Casserole

Easy breakfast casserole recipe with ham, potatoes, and peppers. Perfect for making ahead and feeding a hungry family or to meal prep.
4.91 from 41 votes
Prep Time20 mins
Cook Time55 mins
Total Time1 hr 15 mins
Servings 12 servings
Course Breakfast
Cuisine American

Ingredients 
 

  • 2 tablespoons olive oil
  • 1 ½ pounds Yukon gold potatoes, peeled, cut into ¼" cubes
  • 1 cup red onion, ⅛" dice
  • 1 tablespoon minced garlic
  • 1 cup red bell pepper, ⅛" dice
  • 10 ounces ham, ¼" dice
  • 1 ½ teaspoon kosher salt, divided
  • ¼ teaspoon black pepper
  • ¼ cup sliced green onions
  • 6 ounces sharp cheddar cheese, grated
  • ¼ cup cornstarch
  • 2 ½ cups half-and-half
  • 8 large eggs

Instructions 

  • Preheat the Oven – Set the oven rack to the center position. Preheat to 350ºF (177ºC). Grease a 9×13-inch baking dish with olive oil on the bottom and sides.
  • Saute the Potatoes – Heat a large pan or cast iron skillet over medium-high heat. Add 2 tablespoons olive oil. Once hot, add in the potatoes. Saute until tender, occasionally stirring, for 10 minutes.
  • Saute the Mix-ins – Turn the heat down to medium. Add the onions and garlic, and saute for 1 minute. Add the bell peppers and saute for 2 minutes. Add the ham and saute for 1 minute. Turn off the heat and stir in ½ teaspoon salt, black pepper, and green onions.
    Transfer the mixture to the greased baking dish and spread it into an even layer. Evenly sprinkle half of the cheddar cheese on top.
  • Add the Egg Base – In a large bowl, whisk together the cornstarch and 1 teaspoon salt. Add half-and-half and eggs, and whisk until thoroughly combined. Pour the egg mixture into the baking dish. Evenly sprinkle the remaining cheese on top.
  • Bake the Casserole – Bake for 20 minutes. Rotate the pan and continue baking until the center sets and a toothpick inserted comes out clean, about 20 minutes. The internal temperature should be 180 to 190ºF (82 to 88ºC). Cool for 10 minutes before slicing and serving.

Recipe Video

Nutrition Facts
Breakfast Casserole
Amount Per Serving
Calories 300 Calories from Fat 180
% Daily Value*
Fat 20g31%
Saturated Fat 9g45%
Cholesterol 172mg57%
Sodium 734mg31%
Potassium 472mg13%
Carbohydrates 14g5%
Fiber 1g4%
Sugar 1g1%
Protein 16g32%
Vitamin A 890IU18%
Vitamin C 23.8mg29%
Calcium 196mg20%
Iron 2.8mg16%
* Percent Daily Values are based on a 2000 calorie diet.

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Jessica Gavin

I'm a culinary school graduate, cookbook author, and a mom who loves croissants! My passion is creating recipes and sharing the science behind cooking to help you gain confidence in the kitchen.

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