Classic Egg Bake Casserole

Name: Classic Egg Bake Casserole
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Yield: 8 servings
Cuisine: American
Ingredients: 1 tbsp (14 g) unsalted butter, softened, for greasing the dish; 8 oz (225 g) sturdy white or sourdough sandwich bread, day-old, crusts left on, cut into 1-inch (2.5 cm) cubes (about 6 cups); 1 lb (454 g) bulk breakfast sausage, casings removed if needed; 1 cup (150 g) yellow onion, finely diced (about 1 small onion); 8 oz (225 g) sharp cheddar cheese, freshly shredded (about 2 cups), divided in half; 10 large (500 g) large eggs, at room temperature; 2 cups (480 ml) whole milk, cool or room temperature; 1 tsp (2 g) dry mustard powder; 1 tsp (5 g) kosher salt, Diamond Crystal; use ¾ tsp if using Morton; ½ tsp (1 g) black pepper, freshly ground; 2 tbsp (12 g) scallions, thinly sliced, for garnish (optional)

From the MyKitchenBank Kitchen

A golden, puffed breakfast casserole of savory sausage, sharp cheddar and cubed bread soaked in a creamy egg custard. It feeds a crowd and can be assembled the night before.

Prep: 20 min
Cook: 1 hr
Wait: 40 min
Total: 2 hr
Makes: 1 (9×13-inch) casserole, 8 generous squares

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Ingredients

8 servings

1 tbsp (14 g) unsalted butter, softened, for greasing the dish
8 oz (225 g) sturdy white or sourdough sandwich bread, day-old, crusts left on, cut into 1-inch (2.5 cm) cubes (about 6 cups)
1 lb (454 g) bulk breakfast sausage, casings removed if needed
1 cup (150 g) yellow onion, finely diced (about 1 small onion)
8 oz (225 g) sharp cheddar cheese, freshly shredded (about 2 cups), divided in half
10 large (500 g) large eggs, at room temperature
2 cups (480 ml) whole milk, cool or room temperature
1 tsp (2 g) dry mustard powder
1 tsp (5 g) kosher salt, Diamond Crystal; use ¾ tsp if using Morton
½ tsp (1 g) black pepper, freshly ground
2 tbsp (12 g) scallions, thinly sliced, for garnish (optional)

Equipment (7)

9×13-inch (23×33 cm) baking dish, about 3 quarts
Large skillet (12-inch / 30 cm)
Large mixing bowl
Whisk
Box grater
Instant-read thermometer
Aluminum foil or plastic wrap for covering

Steps

Before you start

Use day-old or lightly toasted bread so the cubes absorb custard without turning mushy. If your bread is fresh, dry the cubes in a 300°F (150°C) oven for 10 minutes first.
Shred the cheddar from a block. Pre-shredded cheese contains anti-caking starch and melts less smoothly.
The casserole needs at least 30 minutes to soak before baking. You can also soak it covered in the fridge overnight (see Make Ahead).
Take the eggs and milk out of the fridge when you start. A custard at room temperature bakes more evenly.

1
Prep dish and bread
- Rub the softened butter over the bottom and sides of a 9×13-inch (23×33 cm) baking dish.
- Cut the bread into 1-inch (2.5 cm) cubes and scatter them evenly across the bottom of the dish.
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Ready when: Bread cubes form an even single layer covering the bottom of the dish.
Tip: Don't pack the cubes down; they need room to absorb the custard.
2
Cook sausage and onion
- Heat a 12-inch (30 cm) skillet over medium-high heat.
- Add the sausage and break it into small crumbles with a wooden spoon.
- Cook 5 minutes, then add the diced onion.
- Continue cooking, stirring occasionally, 5 minutes more.
- Drain off all but 1 tablespoon of fat, or blot with paper towels.
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Ready when: Sausage is browned with no pink remaining and the onion is soft and translucent.
Tip: Excess grease makes the finished casserole heavy and oily, so drain well. Cool the sausage for 5 minutes so it doesn't start cooking the eggs.
3
Layer sausage and cheese
- Spoon the cooked sausage and onion evenly over the bread cubes.
- Sprinkle half of the shredded cheddar (about 1 cup / 113 g) over the top.
- Save the remaining cheese for the topping.
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Ready when: Sausage and cheese are distributed evenly across the dish.
4
Whisk the custard
- In a large bowl, whisk the eggs until the yolks and whites are fully combined and no streaks remain, about 1 minute.
- Whisk in the milk, dry mustard, salt and pepper until smooth.
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Ready when: Mixture is a uniform pale yellow with no visible egg white strands and a slightly frothy surface.
Tip: Whisk the salt in well; undissolved salt leaves bland and salty pockets.
5
Pour and soakOven 350°F / 175°C
- Slowly pour the custard over the bread, sausage and cheese.
- Press down gently with a spatula so all the bread is moistened.
- Sprinkle the remaining cheddar on top.
- Cover and let stand at room temperature for 30 minutes, or refrigerate up to 12 hours.
- During the last 15 minutes of soaking, position a rack in the center of the oven and preheat to 350°F (175°C).
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Ready when: Most of the bread is saturated and the custard sits just below the top of the cubes.
Tip: If it has been refrigerated overnight, let it sit out while the oven preheats and add 5 to 10 minutes to the bake time.
6
Bake until setOven 350°F / 175°C
- Bake uncovered at 350°F (175°C) on the center rack for 45 to 55 minutes.
- If the cheese is browning too fast after 35 minutes, tent loosely with foil.
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Ready when: Top is puffed and golden brown, the center does not jiggle when the dish is gently shaken, a knife inserted in the center comes out clean, and an instant-read thermometer reads 160°F (71°C).
Tip: Check the center, not the edges. A wobbly center means raw egg, so bake 5 more minutes and recheck.
7
Rest before cutting
- Remove the dish to a wire rack and let rest for 10 minutes.
- The casserole will settle slightly and the custard will finish setting.
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Ready when: Edges pull slightly from the dish and the surface no longer looks wet.
Tip: Cutting right away makes the squares slump.
8
Garnish and serve
- Sprinkle with sliced scallions if using.
- Cut into 8 squares (2 rows by 4 rows) and lift out with a wide spatula.
- Serve warm.

Good to know

Tips

Don't skip the soak. Bread that hasn't absorbed the custard bakes up dry on top with eggy pockets underneath.
Use a block of cheese and shred it yourself for a smoother melt.
A glass or light-colored metal dish browns evenly; with a dark metal pan, check 5 minutes early.
Add sautéed bell pepper, spinach (squeezed dry) or mushrooms for variety, but cook out their moisture first so the custard sets.

Make ahead

"Assemble through step 5, cover tightly, and refrigerate up to 12 hours. Bake straight from the fridge, adding 5 to 10 minutes, or let stand at room temperature for 20 minutes while the oven preheats."

Storage & reheating

"Room temperature: up to 2 hours after baking. Fridge: cover and store up to 4 days. Freezer: wrap individual squares tightly and freeze up to 2 months; thaw overnight in the fridge. Reheat squares in the microwave 60 to 90 seconds, or covered with foil in a 325°F (160°C) oven for 15 to 20 minutes, until steaming hot (165°F / 74°C)."

Substitutions

bulk breakfast sausage → diced cooked ham (2 cups / 280 g) or crumbled cooked bacon (8 slices). Skip the browning time; just cook the onion in 1 tablespoon of oil or butter for 5 minutes.
sharp cheddar cheese → Gruyère, Monterey Jack or pepper jack. Use the same weight; pepper jack adds some heat.
whole milk → half-and-half for 1 cup plus 1 cup milk. Gives a richer, creamier custard. Avoid skim, which can turn watery.
sturdy white or sourdough sandwich bread → English muffins, brioche or French bread. Use the same weight of dried cubes; brioche gives a softer, richer texture.