Overnight Omelet Recipe

4.64 / 5 ( 22 Reviews )
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This cheesy egg breakfast casserole can be made up to 24 hours in advance!

overnight egg omelet casserole breakfast recipe

This overnight breakfast casserole is all about the eggs, but lighter and fluffier than scrambled eggs! The mix of eggy custard, bread, and cheese practically melts in your mouth. Simple flavors really allow the eggs shine! America’s Test Kitchen tried out all sorts of different ingredient combinations and this is what they ended up with as the best make-ahead omelet dish!

ingredients for overnight omelet

Even if you’re not a fan of spiciness or mustard, don’t worry about the hot sauce and dry mustard, you can hardly taste them in the finished product. But if you omit them, your casserole may taste a bit bland and one-dimensional.

I bought an onion at the store for this recipe and  somehow it didn’t make it home with me. 🙁 Fortunately, I had some diced onion stashed in the freezer, so I used about a half cup of it in the casserole.

making an overnight 24-hour omelet casserole

The bread can make a big difference in this recipe, so be sure to use a high-quality white sandwich bread. Pepperidge Farm Hearty White bread is highly recommended. By the way, I really love my Victorinox bread knife!

24-hour omelet breakfast casserole

This casserole is nice and simple. Pour the eggy custard over the layers of cubed bread and cheese in the dish. Then just cover with plastic wrap and refrigerate for at least 8 hours, and up to 24 hours. (The texture won’t be as good if you bake it before the 8 hours is up.)

overnight egg omelet dish

Not dry, not soggy, just right! Delicious served with a side of sausage or bacon and fresh fruit! Mmm.

Norpro 994C Silicone Egg Pancake Ring Round, Blue Here are some similar breakfast recipes that you might be interested in:

Overnight Omelet Recipe

Make-ahead breakfast casseroles are super convenient, especially during the holidays and other busy mornings when you want a hearty meal in your tummy. If you're looking for a savory, eggy breakfast for Christmas morning, this overnight omelet casserole is a great option!
4.64 / 5 ( 22 Reviews )
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Cook Time: 1 hour
Total Time: 1 hour
Serves: 8
Adjust Servings: 8


  • 3 tablespoons unsalted butter softened (plus extra for baking dish)
  • 10 slices high-quality white sandwich bread
  • 12 ounces cheddar cheese shredded (about 3 cups)
  • 8 large eggs
  • 3 cups whole milk
  • 1 small onion grated over large holes of box grater
  • 1 teaspoon salt
  • ½ teaspoon pepper
  • 1 teaspoon dry mustard
  • ½ teaspoons hot sauce


  • Butter the bottom and sides of a 9x13 baking dish (or similar size casserole dish). Spread the 3 tablespoons of butter evenly over one side of each slice of bread. Cut the bread into 1-inch pieces. Scatter half of the bread pieces evenly in the prepared dish and sprinkle with half of the cheese. Repeat with remaining bread and cheese.
  • In a large bowl, whisk the eggs until combined, then whisk in the milk, onion, salt, pepper, mustard, and hot sauce. Pour the mixture over the bread. Press lightly on bread to submerge.
  • Cover the dish tightly with plastic wrap and refrigerate for at least 8 hours or up to 24 hours.
  • Preheat oven to 350°F/175°C. Unwrap casserole and bake until puffed and golden, about 1 hour.
  • Serve immediately.

Recipe Notes

Pepperidge Farm Hearty White bread is recommended for this recipe.


Calories: 429kcal | Carbohydrates: 24g | Protein: 23g | Fat: 27g | Sodium: 846mg | Fiber: 2g | Sugar: 8g

Recipe Source: The Best Make-Ahead Recipe Book

Ingredients: Bread, Butter, Cheese, Egg, Hot Sauce, Milk, Mustard, Onion, Pepper, Salt
Meal Type: Breakfast
Categories: Eggs

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