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Sausage Breakfast Casserole

By Martis Guleryan Updated

In short: Brown breakfast sausage, layer it in a 9×13-inch dish with bread cubes and cheddar, pour over eggs whisked with milk and mustard, and bake at 350°F for 45–55 minutes until the center reaches 160°F. Serves 10.

  • 1 hr 20 min
  • 10 servings
  • Easy
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Golden sausage egg and cheese breakfast casserole in a baking dish with one square served on a plate
Illustrative AI-generated photo.

Why you’ll love this recipe

This is the breakfast casserole for holiday mornings and houseguests: you can put it together the night before, slide it in the oven when you wake up, and serve ten people from one dish. The bread soaks up the egg custard so the middle bakes up soft and savory with a golden, cheesy top.

  • Make-ahead friendly — assemble up to 24 hours in advance.
  • Feeds a crowd — one 9×13 dish serves 10.
  • Simple ingredients — sausage, bread, eggs, milk and cheddar.

Getting the custard right

The ratio of eggs to milk decides the texture. About 1 cup of milk for every 5 eggs gives a tender, sliceable custard; more milk makes it softer and wetter in the center. Whisk thoroughly so there are no streaks of white, which can bake into rubbery patches. Because the casserole is thick, the center lags well behind the edges, so check it with a thermometer — egg dishes are safe at 160°F (71°C).

Ingredient substitutions

Instead ofYou can use
Breakfast sausageDiced cooked ham or crumbled cooked bacon (about 2 cups).
Bread cubesA 30-ounce bag of frozen shredded hash browns, thawed, for a gluten-free version.
Whole milk2% milk or half-and-half; skim makes a looser custard.
A square of sausage breakfast casserole on a plate showing bread cubes and melted cheddar

Sausage Breakfast Casserole

Prep
20 min
Cook
50 min
Rest
10 min
Total
1 hr 20 min

Ingredients

Servings
10 servings

Filling

Egg custard

Metric weights use ingredient-specific densities from King Arthur Baking — Ingredient Weight Chart. For baking, weighing is more accurate than cups.

Instructions

Tap a step number to mark it done.

  1. Step 1: Heat the oven and prep the dish

    Heat the oven to 350°F (175°C). Grease a 9×13-inch baking dish with butter or cooking spray.

  2. Step 2: Brown the sausage

    Cook the sausage and onion in a 12-inch skillet over medium-high heat, breaking the meat into crumbles, 8–10 minutes until no pink remains and it reaches 160°F (71°C). Drain off excess fat on a paper towel-lined plate.

  3. Step 3: Layer the casserole

    Spread the bread cubes in the dish. Scatter the sausage and 1½ cups of the cheddar over the top and toss gently with your hands so everything is evenly mixed.

  4. Step 4: Pour in the eggs

    Whisk the eggs, milk, mustard, salt and pepper until no streaks of yolk remain. Pour evenly over the bread and press down with a spatula so every cube is soaked. Sprinkle with the remaining ½ cup of cheese.

    Tip: To make ahead, cover and refrigerate at this point for up to 24 hours. Bake straight from the fridge and add 10–15 minutes.

  5. Step 5: Bake

    Bake uncovered 45–55 minutes, until puffed, golden and set in the center. A knife inserted in the middle should come out clean, and an instant-read thermometer should read 160°F (71°C).

    Tip: If the top browns before the center sets, cover loosely with foil for the rest of the bake.

  6. Step 6: Rest and serve

    Let the casserole rest 10 minutes so it firms up and slices cleanly. Top with green onions, cut into squares and serve.

Equipment

Tips for the best results

  • Dry, day-old bread soaks up the custard without turning mushy. If your bread is fresh, toast the cubes at 350°F for 10 minutes first.
  • Drain the sausage well. Extra grease pools at the bottom of the dish.
  • Shred your own cheddar from a block for a smoother melt.

Storage, reheating and freezing

Refrigerator
Cool, cover and refrigerate within 2 hours. Keeps 3–4 days.
Reheating
Microwave individual squares 60–90 seconds, or warm the covered dish at 350°F (175°C) for about 20 minutes, until it reaches 165°F (74°C).
Freezing
Freeze baked, cooled squares wrapped tightly for up to 2 months. Thaw overnight in the fridge and reheat to 165°F (74°C). The texture is slightly softer after freezing.

Frequently asked questions

Can I assemble breakfast casserole the night before?

Yes. Cover and refrigerate the unbaked casserole for up to 24 hours. The bread soaks up more custard overnight. Add 10–15 minutes to the baking time since it goes in cold.

How do I know the casserole is done?

It should be puffed and set in the center, with no liquid egg when you insert a knife. For certainty, check that the center reaches 160°F (71°C) on an instant-read thermometer.

Why is my breakfast casserole soggy?

Usually the bread was too fresh, the sausage was not drained, or it was underbaked. Use dry bread and bake until the center reaches 160°F (71°C).

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Written by Martis Guleryan

Martis Guleryan is the founder of Joyful Home Cooking and writes and edits the recipes and cooking guides on the site, with a focus on easy weeknight dinners, family-friendly baking and clear, practical steps.

Published , last updated . Read our editorial policy.

Sources and food safety references