Slow Cooker Breakfast Casserole with Bacon and Toast Cubes

Name: Slow Cooker Breakfast Casserole with Bacon and Toast Cubes
Prep time: 20 min
Cook time: 3 h
Total time: 3 h 20 min
Yield: 8 servings
Cuisine: American
Ingredients: 8 slices (320 g) brioche or challah bread, day-old or lightly toasted, cut into ¾-inch cubes; 10 slices (280 g) bacon slices, cooked until crispy and chopped into ½-inch pieces; 10 whole large eggs, at room temperature; 2 cups (480 ml) whole milk; 2 cups (200 g) sharp cheddar cheese, shredded; 1 teaspoon (6 g) kosher salt; ½ teaspoon (1 g) freshly ground black pepper; 1 tablespoon (15 ml) Dijon mustard; 1 tablespoon (14 g) unsalted butter, softened; 3 whole scallions, white and light green parts sliced thin, dark green parts reserved for garnish (optional)

From the MyKitchenBank Kitchen

A hearty, hands-off breakfast casserole made in the slow cooker. Cubed toast, crispy bacon, and sharp cheddar are bound together with a savory custard of eggs and milk, then cooked low and slow until set and golden. Perfect for feeding a crowd or meal-prepping breakfast for the week. Serve warm, straight from the slow cooker.

Prep: 20 min
Cook: 3 hr
Wait: 10 min
Total: 3 hr 30 min
Makes: 8 servings (about 1¼ cups each)

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Steps

Before you start

Cook the bacon the night before if you prefer to simplify morning prep
Cube and toast the bread ahead so it has time to dry out slightly
Use a 6-quart slow cooker; a smaller cooker may overflow
Assemble the casserole in the slow cooker insert the morning you plan to cook it

1
Cook the bacon
- In a large skillet over medium heat, cook the 10 bacon slices until crispy, about 8–10 minutes, stirring occasionally.
- Transfer to a paper towel to cool, then chop into ½-inch pieces.
- You should have about 1¼ cups chopped bacon.
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Ready when: Bacon is browned and crispy, grease is rendered
Tip: Cook bacon completely in advance if preparing the casserole the night before
2
Toast and cube the breadOven 300°F / 150°C
- Cut the 8 slices of brioche or challah into ¾-inch cubes (you should have about 6 cups).
- Spread on a baking sheet and toast in a 300°F (149°C) oven for 10 minutes, stirring halfway through.
- The bread should be warm and slightly firm but not hard.
- This helps it absorb the egg custard without becoming soggy.
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Ready when: Bread cubes are warm and light golden at the edges
Tip: Use day-old bread if possible; fresh bread can absorb too much liquid and become mushy
3
Prepare the egg custard
- Crack the 10 eggs into a large bowl.
- Add 2 cups (480 ml) milk, 1 tablespoon Dijon mustard, 1 teaspoon kosher salt, and ½ teaspoon black pepper.
- Whisk together until fully combined and the mixture is smooth.
- The mustard adds subtle depth and prevents the custard from tasting flat.
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Ready when: Mixture is pale yellow and completely homogeneous
Tip: Bring eggs to room temperature for faster, more even whisking
4
Assemble the slow cooker
- Rub the inside of a 6-quart slow cooker insert with 1 tablespoon softened butter.
- Place the toasted bread cubes on the bottom, then scatter the chopped bacon over the bread.
- Sprinkle 1¾ cups (175 g) of the shredded cheddar evenly over the bacon.
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Ready when: Ingredients are distributed evenly in the slow cooker
Tip: Butter the insert to prevent sticking around the edges
5
Pour in the custard and season
- Slowly pour the egg custard evenly over the bread, bacon, and cheese.
- Using the back of a spoon, gently press down on the bread mixture to help it absorb the liquid.
- Sprinkle the remaining ¼ cup (25 g) cheddar on top.
- Let sit for 5 minutes so the bread begins to soak.
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Ready when: Custard is distributed evenly and bread is beginning to soften
Tip: Pour slowly to avoid air pockets and ensure even soaking
6
Cook low for 3 hours
- Cover the slow cooker and set it to LOW.
- Cook for 3 hours (180 minutes).
- The casserole should cook gently—you're not looking for it to boil or bubble rapidly.
- The edges will set first; the center will still jiggle slightly when you gently shake the slow cooker around hour 2.5.
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Ready when: Edges are set and opaque; center jiggles slightly but is mostly firm
Tip: Avoid lifting the lid; each opening adds 15–20 minutes to the cook time
7
Check for donenessOven 160°F / 70°C
- After 3 hours, insert a knife into the center of the casserole.
- It should come out clean or with a few moist crumbs, not wet custard.
- The internal temperature should reach 160°F (71°C) when checked with an instant-read thermometer at the center.
- If still wet in the middle, cover and cook an additional 15–20 minutes on LOW.
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Ready when: Knife inserted in center comes out clean or nearly clean; internal temp is 160°F (71°C)
Tip: Use a meat thermometer for accuracy; overcooking will dry out the casserole
8
Rest and garnish
- Turn off the slow cooker and let the casserole rest, uncovered, for 10 minutes.
- This allows the structure to set slightly and the temperature to cool just enough for easy serving.
- If using scallions, scatter the light green sliced parts and reserved dark green tops over the surface.
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Ready when: Surface is set but still warm; resting is complete
Tip: Garnish just before serving to keep the scallions fresh and bright
9
Serve
- Using a large spoon or a wide pie server, portion the casserole into bowls or plates.
- Serve warm directly from the slow cooker, or ladle into a serving dish.
- The casserole will continue to firm up as it cools slightly.
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Ready when: Casserole is cut cleanly into portions
Tip: Serve within 1 hour of finishing cooking for the best texture

Good to know

Tips

For a lighter version, substitute skim or low-fat milk for whole milk, and reduce bacon to 8 slices. The casserole will be less rich but still delicious.
Add fresh herbs—try 2 tablespoons finely chopped fresh dill or parsley stirred into the custard for brightness.
To prevent the top from browning too much in a slow cooker, place a layer of parchment paper under the lid; this traps steam and prevents condensation from dripping onto the food.
This casserole reheats beautifully and is ideal for meal prep. Make it on Sunday for grab-and-go breakfasts through Friday.

Make ahead

Assemble the entire casserole in the slow cooker insert the evening before. Cover and refrigerate overnight. In the morning, place the insert directly into the slow cooker base and cook on LOW for 3 to 3.5 hours (add 15–20 minutes since it will start cold). You can also cook the bacon and toast the bread cubes 1 day ahead and store them separately in airtight containers.

Storage & reheating

Refrigerator: Cover and store leftovers in an airtight container for up to 4 days. Reheat individual portions in the microwave on 50% power for 2–3 minutes, or cover and warm the entire casserole in a 325°F (163°C) oven for 15–20 minutes until heated through. Freezer: Cool completely, then transfer to a freezer-safe container or wrap tightly in plastic wrap and foil. Freeze for up to 3 months. Thaw overnight in the refrigerator, then reheat as directed above. Do not freeze longer than 3 months, as the texture may become grainy.

Substitutions

sharp cheddar cheese, shredded → Gruyère, Monterey Jack, or a blend of cheddar and Fontina. Use the same amount. Gruyère adds nuttiness; Monterey Jack is milder and slightly creamier.
brioche or challah bread, day-old or lightly toasted → Sourdough, Italian, or whole-wheat bread. Avoid soft white sandwich bread, which absorbs too much custard and becomes mushy. Day-old bread works best.
whole milk → Heavy cream mixed with water (1 cup cream + 1 cup water), or half-and-half. Cream-based custard will be richer and slightly thicker. Use the same total volume.
bacon slices → Sausage, diced ham, or smoked turkey. Cook sausage fully before adding. Use the same quantity. Each adds different flavor but maintains the protein balance.