Breakfast Sausage Casserole Recipe

This breakfast casserole is so simple to make that I can prepare it the night before and put it in the oven the next morning. When I need to make breakfast for a large group, I like using this recipe because it saves me so much time in the mornings. I just brown some sausage, combine it with some bread, eggs, milk, and cheddar cheese, and let it sit overnight in the fridge.

Take it out in the morning, put it in the oven, and in 45 minutes you've got a boiling casserole loaded with sausage and cheese that feeds 12! It's been at our Christmas morning table for years and is always the first dish to disappear.

The Breakfast Morning I Make This For

This has been on our family Christmas morning table for as long as I can remember. It’s one of those recipes that doesn’t need to be reinvented or improved. It has simple ingredients, can be assembled the night before, and baked the next morning.

No one is stuck in the kitchen! And that is especially wonderful on Christmas morning. While the kids are opening presents, coffee is brewing, and the casserole is doing its thing in the oven.

Why the Overnight Rest Makes All the Difference

Overnight rest is key. When you soak the bread in the egg mixture, it absorbs all of the liquid. By the time you place it in the oven, the bread is not sitting in liquid. The bread and egg have fused into one solid casserole that will bake evenly and slice nicely.

Dry mustard is an essential ingredient. Just one teaspoon won't make your casserole taste like mustard — it will add a depth and a slight tang that will make the egg mixture more interesting. Don't skip it.

No morning work at all. All you do on the morning of is take it out of the fridge and put it in the oven. That's it. Easy for Christmas morning, Easter brunch, or any time you're entertaining for breakfast and want to be able to enjoy the meal instead of slaving away in the kitchen.

It feeds a lot of people; the whole recipe yields approximately 12 big servings. It is simple to halve for a smaller group.

Seven Ingredients — and Why Dry Mustard Is the One People Skip

Breakfast sausage (1 lb.)

To get started, brown the sausage and then drain it. I like to use sage breakfast sausage since it gives the best flavor. I wouldn't suggest using Italian sausage since the fennel tends to throw off the flavor profile. If your guests can handle a little spice, feel free to use hot sausage as a great upgrade! You could also switch things up and use ham in place of sausage.

White bread (8 slices)

White bread used in a rectangle is classic and does the trick. It will be buttered and pressed butter side down into the pan, then the egg mixture will be soaked into it overnight. In fact, bread that is a day old soaks up the mixture a little better than fresh bread.

Make sure to steer clear of really dense breads such as sourdough. They can create uneven textures because they are not easily absorbed.

Eggs (6)

The base of the custard. Using six eggs for a full 9×13 casserole gives you a set, sliceable result. Don’t be tempted to use fewer — it makes the casserole too soft and it won’t hold together when you cut it.

Milk (2 cups)

2% milk will work, but for the best result use whole milk. Skim milk will not work at all since the custard won't set up properly. I tried it with skim once, and it came out watery. Not worth the trade-off.

Dry mustard (1 teaspoon)

This is the ingredient that people miss and then wonder why their casserole has no flavor. Don't substitute with prepared mustard — the dry one spreads throughout the egg mixture. It's a tiny amount but it really does make a difference.

Salt (1 teaspoon)

The egg mixture needs some seasoning. One teaspoon does the trick for the entire recipe — it seasons everything, including the bread.

Sharp cheddar cheese (1 cup, grated)

For the best flavor, use sharp cheddar cheese. If possible, grate it yourself. Pre-shredded cheese clumps together and doesn't melt into the custard as well as freshly grated cheese. To get even distribution, stir the cheese into the egg mixture instead of just sprinkling it on top.

How to Make Overnight Breakfast Sausage Casserole

The Night Before: Assemble the Casserole

First, brown and drain your sausage and set it aside to cool. Next, butter your slices of bread and press them, butter-side down, into a greased 9×13 baking dish so that they cover the entire bottom.

In a bowl, combine the eggs, and milk, and season with dry mustard and salt. Whisk until combined. Next, add the grated cheddar and the browned sausage and mix.

Evenly distribute the mixture over the bread in the dish. Then, cover it and let it chill in the fridge for a minimum of 8 hours; overnight is better. Be sure to not skip this step, as it is crucial for everything to set properly.

Morning of: Bake and Serve

While the oven preheats to 350°, remove the dish from the fridge. Bake uncovered for 40 to 45 minutes. The dish is finished when the top is golden brown and the center is set; a knife inserted in the center should come out clean with no wet egg.

It's totally normal for the casserole to puff up a little while baking, and then settle when it cools. Be sure to let it rest for 5 minutes before cutting. If you cut it too early it will fall apart.

Five Things Worth Getting Right With This Casserole

• Give it the full overnight rest. The minimum is 8 hours, but overnight is better. The bread needs time to fully absorb the egg mixture. If you rush it, the bottom will be soggy and uneven instead of set.
• Drain the sausage well. Excess grease left in the sausage will make the casserole greasy. Brown it, drain it, and let it cool before adding to the egg mixture.
• Don’t skip the butter on the bread. Pressing buttered bread butter-side-down into the dish adds richness and helps prevent the bread from getting too soggy on the bottom during the long overnight soak.
• Check for doneness in the center. The outside will look done before the middle is. Use a knife or toothpick in the very center to make sure it comes out clean before pulling it from the oven.
• Let it rest before cutting. 5 minutes of rest lets the custard firm up enough to slice cleanly instead of falling apart in the pan.

What This Works Best Alongside

This casserole can be paired with fresh fruit or a simple fruit salad, and on the side, some orange juice, toast or pastries, and hot sauce or salsa on top (it’s great with both).

It’s great for Christmas morning (assemble on Christmas Eve and bake while kids are opening gifts), Easter brunch, Mother’s Day breakfast, weekend brunch with company, or meal prep since leftovers are easily reheated for quick weekday breakfasts.

How to Store It and What to Do With Leftovers

Fridge: Food stored in the fridge can last a maximum of four days. When reheating portions, you may do so in the microwave for 1-2 minutes. If you're going to leave the pan in the oven, cover it with foil and set it to 325°. Remove after 15-20 minutes.

Freezing Tips: This casserole is great for freezing! Just bake it and let it cool. After that, wrap the individual portions in plastic wrap. They will be good for 2 months. Just make sure to thaw them overnight in the fridge beforehand. You can reheat it in the microwave or oven.

Make-ahead note: The casserole must sit in the fridge for at least 8 hours before you bake it. You can also prepare it up to 24 hours ahead of time — an extra night in the fridge won't hurt it.

A leftover move you should try is crumbling a slice into a skillet with a bit of butter and crisping it up like a hash. Add a fried egg and hot sauce. It's a totally unique and delicious way to use what's leftover.

Six Ways to Change Up This Casserole

Ham version: Replace the sausage with 1–2 cups of diced cooked ham. This is great for using holiday ham leftovers—many families have this as the classic Christmas-morning variation.

For the bacon version, you can use cooked, crumbled bacon instead of sausage. Approximately 8-10 slices of bacon will add a smoky flavor.

You can add some vegetables! Consider using diced bell pepper, chopped onion, or sliced mushrooms. You can sauté them and mix them with the sausage. Just be sure to dice the vegetables small so everything distributes evenly.

Cheddar can be substituted with Colby Jack cheese, Monterey Jack cheese, or Pepper Jack cheese. If you want to increase the spiciness of your dish, go with Pepper Jack.

For bread swaps, Texas toast, thick-cut sandwich bread, and even croissant halves (for a more indulgent option) can be used. The thicker the bread used, the more filling the casserole will be.

For a gluten-free option, substitute with gluten-free sandwich bread. All other ingredients in this recipe are gluten-free.

The Two Kitchen Details That Help This Come Out Right

This casserole is so simple, that only a few notable details stand out:

An ideal 9×13 baking dish would be made of Pyrex and have a lid! This way you can put the dish in the fridge without having to deal with any plastic wrap. You can also easily transition the dish to the oven. A good Pyrex 9×13 baking dish will also give you good edge to center heat distribution so you won't have to worry about the edges overcooking before the center sets.

Sharp cheddar cheese is best used freshly grated. Any shredded cheese has anti-caking agents, which makes the cheese not melt smoothly into the custard. A block of Tillamook Sharp, which is consistently good, sharp cheddar cheese grated fresh, will melt into the egg mixture and redistribute evenly the way it is supposed to.

Breakfast Sausage Casserole FAQ

Can I bake this without refrigerating overnight?

You're correct, but the quality of the texture will be impacted negatively. If you're pressed for time, it should be set aside for at least 2 hours; the bread needs to absorb the egg mixture first, or you'll end up with bread that is just soggy and swimming in liquid rather than bound together in a casserole. It really is worth planning for an overnight set aside time.

Can I use crescent roll dough instead of bread?

Yes, press unrolled crescent roll dough into the bottom of the baking dish instead of bread slices. It bakes into a flakier, richer base. You can also use canned biscuit dough cut into pieces. Both variations are delicious and honestly a nice upgrade if you want something a little more special.

Can I double this recipe?

Yes, you can use two 9×13 pans or one very large roasting pan. You will also double all of the ingredients. Baking time may need an additional 10-15 minutes if you have thicker layers. Remember to do the knife test in the center to determine this, not the timer.

My casserole is jiggly in the center — is it done?

A small jiggle is nothing to worry about, and it isn't an indicator that it's undercooked. You can also do a knife test. Insert a knife in the middle, and if it pulls out clean, then it's good to go. It will also firm up while it's resting.

If the knife comes out with the wet, raw egg on it, give it another 5 to 10 minutes, and check again. Don't pull it just because the timer says to.

Can I make it vegetarian?

Yes—sautéed bell peppers, onions, mushrooms, or spinach are great additions. Aim for about 1-2 cups total. Sautéing them will remove their moisture so the casserole doesn’t get too soggy while baking.

Other Breakfast Casseroles Worth Making

Biscuits and Gravy Casserole — home made sausage gravy layered on two sections of buttery biscuits. One pans feeds a lot and once it's in the oven it's completely hands off.

With this Easy Bacon and Egg Breakfast Casserole you can prepare a breakfast with delicious crispy bacon, eggs, and cheese. You can easily put this cheese and egg casserole together quickly, and you can make it the night before to have it ready for the morning.

Sausage Croissant Breakfast Casserole combines sausage, egg, and cheese like all the others, but this one is built on a croissant base. It's a little more indulgent and perfect for a special occasion.

If you prepare this breakfast sausage casserole, make sure to leave a comment below telling me how it went.