Overnight Egg Casserole

Article by Kelly Vaughan

This overnight egg casserole is an ideal breakfast or brunch to assemble up to a day ahead and bake off in the morning. Save this recipe for the next time you’re hosting guests and need an easy breakfast or brunch dish that will feed a crowd without a ton of effort.

An egg casserole typically features a variety of different types of meat, cheese and vegetables. Peek in your fridge or see what looks good at the farmers’ market and feel free to get creative with your add-ins. This version features lean turkey sausage, frozen and thawed spinach, scallions, cheddar, and Parmesan cheese. Healthy cooking doesn't always mean using low-fat products. The full-fat cheddar and Parmesan together are so satisfying in this easy casserole that a little goes a long way, and they're a terrific complement to turkey sausage and dark leafy greens.

How to Make Overnight Egg Casserole

Add hearty, protein-packed fillings. The beauty of an egg casserole is that you can customize it based on what you have in the fridge or freezer. This recipe calls for lean turkey sausage, which has so much texture, flavor, and is a nutritious source of protein.

Include a variety of cheese. To keep this egg casserole from being too one-note, use a blend of cheeses like cheddar and Parmesan. Cheddar is meltable and sharp, while the Parmesan adds a salty, savory edge. The two complement each other perfectly in this casserole.

Incorporate bread cubes. By folding bread cubes into the egg mixture, the casserole becomes a dish that’s halfway between an upside-down quiche and a savory bread pudding. Be sure to use a hearty boule (ideally one that’s a day or two old) so that it soaks up the custard without turning soggy.

Ingredient Swaps

There are so many ways that you can adjust this recipe to fit your flavor preferences. This recipe calls for 1% milk but you can use 2% or whole; the custard will be richer and creamier, but we don’t think that’s a bad thing.

You can also use another salty hard cheese in place of the Parmesan cheese such as Pecorino Romano or Grana Padano.

Not a fan of turkey sausage? Try pork sausage, chopped ham, or crumbled bacon instead.

How to Store Overnight Egg Casserole

You can store the unbaked casserole in the refrigerator for up to 24 hours or in the freezer for up to two weeks. Cover tightly with plastic wrap.

To store leftovers, let the casserole cool completely before storing. We recommend cutting individual portions and storing them in an airtight container. Smaller portions will reheat more quickly than the entire casserole, which means you can get breakfast on the table in a snap.

How to Serve Overnight Egg Casserole

This overnight egg casserole is best served straight from the oven. To complete your breakfast or brunch spread, you can serve it alongside a light green salad, strips of crispy bacon, or a colorful fruit salad.

Overnight Egg Casserole FAQs

What are the ingredients for a breakfast casserole?

Breakfast casseroles are a versatile, crowd-friendly dish. A traditional breakfast casserole is made with eggs, milk or cream, meat (such as chopped bacon or ham), fresh vegetables, cheese, salt and pepper. Sometimes, home cooks will add frozen shredded hash browns or another type of potato for a bit more heft.

Can breakfast casserole be made the night before?

Yes! This breakfast casserole is best assembled 12 to 24 hours in advance of serving. That way, the bread cubes will have time to absorb some of the egg mixture so that they get soft and chewy, plus all of the other ingredients will be able to marry together to create a flavorful bite.