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Overnight breakfast casserole on a white plate.

Overnight Breakfast Casserole

Your easy Brunch menu savior: Overnight Breakfast Casserole. Prepare to dive into a savory ham, cheese, and egg custard topped with an irresistible buttery cornflake topping. This is one of the best make-ahead breakfast recipes to have in your repertoire!
Course Breakfast
Cuisine American
Prep Time 15 minutes
Cook Time 2 hours 30 minutes
Chill Time 8 hours
Total Time 10 hours 45 minutes
Servings 12 servings
Calories 534kcal


For the casserole:

  • 1 loaf English muffin bread sliced (see note 1)
  • 1/2 cup butter softened (1 stick)
  • 2 cups shredded Swiss cheese (see note 2)
  • 6 slices deli ham (see note 3)
  • 2 cups shredded cheddar cheese
  • 1 tablespoon fresh parsley or 1 teaspoon dried parsley
  • 1 tablespoon fresh dill or 1 teaspoon dried dill
  • 1 teaspoon dried mustard (see note 4)
  • Salt and freshly ground black pepper
  • 3 cups milk
  • 10 large eggs

For the topping:

  • 1 1/2 cups corn flakes (see note 5)
  • 3 tablespoons butter melted


To make the casserole:

  • Coat a 9-inch by 13-inch baking dish with nonstick spray. Spread butter on one side of each bread slice and lay half (about 6 slices) face up in prepared baking dish.
  • Top with Swiss cheese, ham slices, and cheddar cheese. Sprinkle with parsley, dill, mustard, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Top with a second layer of bread, butter-side up.
  • Combine milk and eggs in a blender and process for 30 seconds (or whisk vigorously in a large bowl by hand). Pour evenly over the top of casserole. Cover with foil and refrigerate at least 8 hours or overnight.

To bake the casserole:

  • Preheat oven to 275 degrees. Bake covered casserole for 30 minutes. While the casserole is baking, combine corn flakes and butter and mix well to combine.
  • Remove casserole from oven. Increase oven temperature to 350 degrees. Remove foil and spread topping. Return to oven and bake, uncovered, for 45 minutes. Let stand 15 minutes before serving.


  1. English muffin bread: Different from actual English muffins, English muffin bread is hearty and chewy and perfect to stand up to all the layers of this casserole. If you can’t find it, don’t despair; any soft, coarse-textured white sandwich bread (or even buttery croissants cut in half lengthwise) will work.
  2. Cheese: I love the flavor combination of Swiss and cheddar, but feel free to use a combination of any melty cheeses.
  3. Deli ham: Or opt for thin slices of leftover ham from your holiday roast.
  4. Dried mustard: Powdered mustard gives a little savory kick to the egg custard. To use yellow or Dijon mustard, substitute an equal amount and add it to the blender with the eggs.
  5. Corn flakes: Similar to dinner casseroles that call for crushed Ritz crackers or bread crumbs on top, these add a breakfast-appropriate, delightfully crunchy element to the top of this casserole.
  6. Yield: This Overnight Breakfast Casserole recipe makes 12 brunch entree-sized servings. Scale up or down as desired; this is a very forgiving recipe and can take a lot of improvisation. Just increase the egg and milk mixture to cover what you're making.
  7. Storage: Store leftovers covered in the refrigerator for up to 4 days.


Serving: 1slice | Calories: 534kcal | Carbohydrates: 36g | Protein: 26g | Fat: 32g | Saturated Fat: 13g | Cholesterol: 206mg | Sodium: 845mg | Potassium: 323mg | Fiber: 2g | Sugar: 7g | Vitamin A: 1216IU | Vitamin C: 1mg | Calcium: 453mg | Iron: 4mg