Overnight Sausage and Egg Breakfast Casserole

This sausage and egg breakfast casserole is the kind of dish that lets you sleep in and still set a hot, satisfying meal on the table. Cubed bread soaks up a savory egg custard, browned sausage, and sharp cheddar overnight, then bakes into a golden, puffy centerpiece.

It is built for feeding a crowd without a last minute scramble, and the results are reliably good every time. The top gets crisp while the inside stays soft and custardy.

What Makes This Casserole So Good

The overnight soak is the reason this works so well. The bread absorbs every bit of the egg mixture, so every bite is seasoned through instead of tasting like plain bread with egg on it.

The custard ratio keeps the texture tender without getting wet. Whole milk gives it body, and the cheese melts into pockets that pull apart nicely.

You get a savory, peppery flavor from the sausage and sharp cheddar, and that little bit of dry mustard brightens the whole dish without anyone guessing it is there.

Ingredients

• 1 lb bulk pork sausage: breakfast-style, not Italian; turkey sausage works fine here too
• 8 large eggs: room temperature eggs blend more smoothly
• 2 cups whole milk: 2% milk works, but whole milk gives the richest custard
• 1 tsp dry mustard: adds a gentle, savory warmth, not heat
• ½ tsp salt: adjust if the sausage is very salty
• ¼ tsp black pepper: freshly ground
• 6 cups cubed day-old bread: a sturdy loaf like French or Italian, cut into 1-inch pieces
• 2 cups shredded sharp cheddar cheese: off-the-block melts and tastes better than pre-shredded
• Optional: ¼ cup sliced green onions: for a fresh, mild bite on top after baking

Variations and Substitutions

• Sausage swap: Use sage or maple breakfast sausage, or skip the pork and brown ground turkey or chicken with a pinch of fennel seed. Plant-based crumbles also hold up well here.
• Bread choices: Challah, brioche, or croissant pieces make a richer casserole because of the butter content. Reduce milk to 1¾ cups if the bread is very soft.
• Cheese switch: Smoked gouda or pepper jack melt into a different sort of savory note. Stick with a good melting cheese so the top gets that glossy browned color.
• Add some vegetables: Sautéed bell pepper, mushrooms, or spinach work well. Cook them down first so they do not release water into the bake.
• Dairy-free option: Replace whole milk with unsweetened, full-fat oat milk and use a plant-based cheese that melts well. The custard will set just fine.

For a smaller, hand-held version, try a sausage and egg breakfast burrito with the same flavors.

How to Make Overnight Sausage and Egg Breakfast Casserole

Step 1: Brown the Sausage

Set a large skillet over medium-high heat. Crumble in the 1 lb bulk pork sausage and cook, breaking it up with a spatula, for about 8 to 10 minutes until it is fully browned and no pink remains.

The sausage should look deeply golden in spots, with some crispy edges. Drain off the fat and set the sausage aside to cool slightly while you prep the rest.

Step 2: Layer the Bread and Sausage

Spread the 6 cups of bread cubes evenly into a greased 9-by-13-inch baking dish. Scatter the browned sausage over the bread, then sprinkle on the 2 cups of shredded sharp cheddar.

At this stage, the dish will look mostly full, with cheese nestled around the bread and sausage. Use your hands or a large spoon to toss everything gently so the sausage and cheese get distributed between the cubes.

Step 3: Whisk and Pour the Custard

In a large bowl, whisk together the 8 eggs, 2 cups whole milk, 1 tsp dry mustard, ½ tsp salt, and ¼ tsp pepper until the mixture is smooth and a little frothy. Pour the custard slowly and evenly over the layered ingredients in the dish.

The liquid will settle around the bread. Press down gently on the top pieces with the back of a spoon so they all get a good soak. The egg mixture will still be visible in spots, and that is exactly what you want.

Step 4: Bake Until Puffed and Golden

Preheat the oven to 350°F (175°C). Cover the dish with foil and bake for 30 minutes, then remove the foil and continue baking for another 20 to 25 minutes. The total bake time will be 50 to 55 minutes.

You will know it is ready when the center is set and no longer jiggles, a knife inserted near the middle comes out clean, and the top is deep golden with a few browned cheese spots. If you like a darker top, leave it in 2 or 3 extra minutes.

Step 5: Slice and Serve

Let the casserole rest for about 5 minutes after pulling it from the oven. This helps the custard firm up just enough to cut clean squares. Slice into portions and lift them out with a spatula.

Scatter the optional green onions over the top right before serving. The savory, eggy scent and the contrast of the crisp top against the soft interior look even better than they taste.

Tips for the Best Casserole

• Use stale bread: A day-old, slightly dry loaf soaks up the custard without turning to mush. If your bread is fresh, spread the cubes on a sheet pan and toast them at 300°F for 8 to 10 minutes, then let them cool.
• Chill overnight for clean slices: The casserole cuts and holds its shape much better when the custard has time to fully hydrate the bread. An overnight rest also means less work in the morning.
• Brown the sausage well: Get some color on the meat before layering it in. Those browned bits add a deeper, savory note to the whole bake.
• Grate your own cheese: Pre-shredded cheese is coated to prevent clumping, and it does not melt nearly as smoothly. A block of sharp cheddar grated right before assembly melts into creamier pockets.
• Line your dish if you like an easy cleanup: A parchment sling with overhang makes it simple to lift the whole casserole out for slicing and serving.

Bake times by pan size:

Storing Leftovers

• Refrigerate: Cover the cooled casserole tightly and store it in the fridge for up to 4 days.
• Reheating: Warm individual portions in the microwave for about 1 to 2 minutes, or place the whole baking dish covered with foil in a 325°F oven for 15 to 20 minutes.
• Freeze: You can freeze the baked casserole, sliced into portions, for up to 2 months. Thaw overnight in the refrigerator before reheating.

What to Serve With Sausage and Egg Breakfast Casserole

A bright citrus salad with segments of orange and grapefruit cuts through the richness of the custard and cheese. A simple arugula salad dressed with lemon and olive oil adds a peppery, fresh contrast. For something sweet, fresh berries or a fruit compote spooned over plain yogurt keeps the plate balanced without being heavy.

Frequently Asked Questions

Can I use bacon or ham instead of sausage?

Yes. Cook and crumble 1 lb of bacon, or dice leftover ham into small pieces. Both bring a slightly different salt level, so taste the custard mixture for seasoning before pouring it over.

Do I really have to let it sit overnight?

The casserole needs at least 4 hours in the fridge for the bread to absorb the custard. An overnight rest gives the best texture, but a shorter soak still works if you are in a hurry.

Can I make this without bread?

You can, but it becomes a frittata-like bake. Omit the bread, reduce the milk to ½ cup, and bake until the center is set, about 25 to 30 minutes. The texture will be denser and more egg-forward.

How do I know when it is fully cooked?

The center should not jiggle when you shake the dish, and a thin knife inserted an inch from the middle should come out clean. An instant-read thermometer will read 160°F if you want to be sure.

Can I add vegetables without making it soggy?

Absolutely. Sauté any vegetables like mushrooms, bell peppers, or spinach until they release their water and look dry. Adding them raw releases too much liquid during baking and makes the casserole watery.

Sausage and Egg Breakfast Casserole Recipe

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 50 minutes mins

Total Time 1 hour hr 10 minutes mins

Servings: 8 servings

Calories: 430

Ingredients Method Notes

Ingredients

  

• 1 lb bulk pork sausage
• 8 large eggs
• 2 cups whole milk
• 1 tsp dry mustard
• ½ tsp salt
• ¼ tsp black pepper
• 6 cups cubed day-old bread
• 2 cups shredded sharp cheddar cheese
• ¼ cup sliced green onions (optional)

Method

 

1. Brown the sausage in a skillet over medium-high heat, breaking it up, for 8 to 10 minutes until fully cooked, then drain and set aside.
2. Layer the bread cubes, browned sausage, and shredded cheese in a greased 9-by-13-inch baking dish, tossing gently to distribute.
3. Whisk the eggs, milk, dry mustard, salt, and pepper until smooth, pour evenly over the bread mixture, and press down gently to submerge the top cubes.
4. Cover and refrigerate at least 4 hours or overnight. Preheat the oven to 350°F (175°C), then bake covered with foil for 30 minutes, uncover, and bake another 20 to 25 minutes until the center is set and the top is golden.
5. Let the casserole rest 5 minutes before slicing. Top with green onions if using, and serve warm.

Notes

Refrigerate the assembled casserole at least 4 hours or overnight for the best texture. Leftovers reheat well in the microwave or a low oven. The green onions add a fresh pop, but they are best added right before serving so they stay crisp.