Brunch will be smooth sailing, all thanks to this recipe for Overnight Breakfast Casserole. It's a culinary miracle of ham, cheese, and savory egg custard, baked with an irresistible buttery cornflake topping.
While everyone’s fast asleep, the English muffin bread soaks up the herb and egg mixture and becomes more like savory, stuffed French toast. In the morning, the only thing left to do is pop it in the oven and brew some coffee.
Oh, and make the crispy cornflake topping. But that’s it. Promise!
Need Overnight Breakfast Casserole for a crowd? Click and slide the number next to “servings” on the recipe card below to adjust the ingredients to match how many you’re feeding—the recipe does the math for you, it’s that easy.
Overnight Breakfast Casserole ingredients:
Grab this list at the store, if you don’t already have it.
- English Muffin Bread.
- Swiss cheese.
- Cheddar cheese.
- Deli ham.
- Parsley, fresh or dried.
- Dill, fresh or dried.
- Dried mustard.
- Salt and pepper.
English Muffin Bread…what is it?
Loaf-style English muffin bread is a little different than the craggy, chewy round toaster muffins in the narrow, rectangular boxes, but it’s every bit as good. Chances are you’ve walked by this type of bread a million times at the grocery store but haven’t noticed it.
- English Muffin Bread is made by these brands (and probably others):
- Country Hearth
If you still can’t find it, don’t despair; any soft, coarse-textured white sandwich bread will work splendidly.
How to prep Overnight Breakfast Casserole:
You need a 9-inch by 13-inch baking dish to make this recipe, as it is, but feel free to go bigger. Luckily, it’s a very forgiving recipe and can take all the improvisation you can give it. Just increase the egg and milk mixture to cover what you're making.
- To start, butter or grease the baking dish with non-stick spray. Then butter one side of the bread slices and fit half of them, butter side up, in the baking dish—snug, but not overlapping.
- Then, from edge to edge, top the buttered bread with Swiss cheese, then ham, and finally cheddar cheese.
- Next, sprinkle on the parsley, dill, and dried mustard powder. Then season with salt and pepper.
- To make the egg custard, whisk together the milk and the eggs. You can do this quickly in a blender or by hand. Pour the egg mixture over the top of casserole and give the baking dish a little jiggle to make sure the eggs are distributed evenly.
- Cover the baking dish with foil and refrigerate overnight. Then get some sleep!
How to bake Overnight Breakfast Casserole:
- Preheat the oven to 275 degrees. It’s a lower heat than you’d think, but those eggs need to cook gently at first!
- Bake the covered egg casserole for 30 minutes. Meanwhile, you can make the crunchy cornflake topping.
- Mix together the cornflakes and the melted butter. Take out the casserole and turn the oven to 350 degrees. Then remove the foil and scatter the buttered cornflakes over the top of everything.
- Back to the oven. Bake the uncovered casserole for 45 minutes. Take it out and let it stand for 15 minutes before serving, if you can wait that long.
Other overnight breakfast casserole inspiration:
Switch up the bread. Try this recipe with plain butter croissants sliced in half. It’s a great way to use that big package from Costco! This recipe is definitely made with bread, but you can use gluten-free bread in place of the English muffin bread. Please leave a comment if you’ve tried it!
Overnight breakfast casserole with bacon. Slices of pre-cooked bacon in place of ham? Don’t mind if I do!
Overnight breakfast casserole with sausage. Crumbled, precooked sausage or thin slices of cooked breakfast sausage layered between the bread. Absolutely delicious!
Tater tots. If you’re craving a breakfast casserole with hash browns, mosey on over to Tater Tot Casserole, aka hot dish.
Help! I don’t have any mustard powder! Is there a substitute?
That’s okay. Blend in a teaspoon of Dijon mustard, smooth or whole grain, in with the eggs. You just need a small amount for the savory kick it gives.
Overnight Breakfast Casserole Recipe
For the casserole:
- 1 loaf English muffin bread sliced
- 1/2 cup butter softened (1 stick)
- 2 cups shredded Swiss cheese
- 6 slices deli ham
- 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
- Salt and freshly ground black pepper
- 3 cups milk
- 10 large eggs
For the topping:
- 1 1/2 cups corn flakes
- 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.