Grilled Cheese Sausage & Egg Breakfast Casserole combines everything people love about a hearty breakfast—savory sausage, fluffy eggs, buttery toasted bread, and plenty of melted cheese—in one warm, comforting casserole. It’s ideal for weekend breakfasts, brunch gatherings, holidays, or meal prep because much of the work can be done ahead of time.

The bread absorbs the seasoned egg mixture while baking, creating a tender center, while the cheese melts throughout the casserole and develops a delicious golden top.

Prep time: 25 minutes
Cook time: 40–50 minutes
Total time: About 1 hour 15 minutes
Servings: 8–10
Calories: Approximately 450–550 calories per serving, depending on the sausage, bread, and cheese used.

Ingredients

For the Casserole

1 lb (450 g) breakfast sausage
8 large eggs
2 cups whole milk
½ cup heavy cream
8 slices sandwich bread
3 tablespoons butter, softened
2 cups shredded cheddar cheese
1 cup shredded mozzarella cheese
½ teaspoon garlic powder
½ teaspoon onion powder
½ teaspoon smoked paprika
½ teaspoon salt
¼ teaspoon freshly ground black pepper
2 tablespoons chopped fresh parsley or green onions

Optional Add-Ins

½ cup diced bell peppers
½ cup diced onion
½ cup cooked and crumbled bacon
¼ teaspoon red pepper flakes
½ cup sliced mushrooms
1 small jalapeño, finely chopped

Instructions

1. Prepare the Baking Dish

Preheat your oven to 350°F (175°C).

Lightly grease a 9 × 13-inch baking dish with butter or nonstick cooking spray.

Set it aside while preparing the sausage.

2. Cook the Breakfast Sausage

Place a large skillet over medium heat.

Add the breakfast sausage and cook for approximately 7–9 minutes, breaking it into small pieces with a wooden spoon as it cooks.

Continue cooking until the sausage is browned and completely cooked through.

Drain excess grease from the skillet and set the sausage aside.

If you’re adding onions, peppers, or mushrooms, sauté them with the sausage during the final few minutes of cooking.

This adds extra flavor while also removing some of the vegetables’ excess moisture.

3. Prepare the Grilled Cheese Bread

Spread a thin layer of softened butter over the bread slices.

Heat a skillet or griddle over medium heat.

Place several bread slices butter-side down.

Sprinkle cheddar and mozzarella over the bread, then cover with another bread slice, butter-side facing upward.

Cook for approximately 2–3 minutes per side, or until golden brown and the cheese begins to melt.

Repeat with the remaining bread.

You don’t need to make the sandwiches extremely crispy because they’ll continue cooking in the casserole.

Allow the grilled cheese sandwiches to cool for a few minutes.

Cut them into approximately 1-inch cubes.

These cheesy bread pieces become the foundation of the casserole.

4. Assemble the Casserole

Arrange approximately half of the grilled cheese cubes across the bottom of your prepared baking dish.

Scatter half of the cooked sausage over them.

Add another light layer of shredded cheddar.

Repeat with the remaining grilled cheese pieces and sausage.

Finish with another generous handful of cheese.

Try to distribute everything evenly so each serving contains bread, sausage, eggs, and plenty of melted cheese.

5. Prepare the Egg Mixture

Crack the eggs into a large mixing bowl.

Add the milk and heavy cream.

Season with garlic powder, onion powder, smoked paprika, salt, and black pepper.

Whisk vigorously until the eggs and milk are completely combined.

Pour the egg mixture slowly and evenly over the casserole.

Use the back of a spoon or spatula to gently press the bread into the liquid.

Let the casserole rest for approximately 10–15 minutes before baking.

This gives the bread time to absorb some of the egg mixture.

6. Add the Cheese

Sprinkle the remaining cheddar and mozzarella generously over the top.

For an especially cheesy casserole, add another ½ cup cheddar.

A combination of cheeses gives the dish a better balance of flavor and texture. Cheddar provides a sharp, savory flavor, while mozzarella creates those irresistible melted cheese pulls.

7. Bake

Cover the baking dish loosely with aluminum foil.

Bake at 350°F (175°C) for approximately 25–30 minutes.

Remove the foil and continue baking for another 15–20 minutes, or until the center is set and the cheese on top is melted and lightly golden.

The exact cooking time can vary depending on the depth of your baking dish.

To check for doneness, insert a knife near the center. The eggs should be set rather than liquid.

8. Rest Before Serving

This step is important.

Remove the casserole from the oven and allow it to rest for approximately 10 minutes.

Resting gives the eggs time to finish setting and makes the casserole much easier to slice.

Sprinkle chopped parsley or green onions over the top before serving.

How to Make the Best Breakfast Casserole

The secret to a great Grilled Cheese Sausage & Egg Breakfast Casserole is balancing the textures.

You want the bread to absorb enough egg mixture to become tender without turning mushy. That’s why lightly grilling the bread first works so well.

The toasted exterior provides some structure while the cheese inside melts into the egg mixture during baking.

Meanwhile, browning the sausage before assembling the casserole develops deeper savory flavors.

Draining excess sausage grease is also important. Too much grease can make the bottom of the casserole oily.

Tips for Perfect Results

Use slightly sturdy bread. White sandwich bread works, but brioche, sourdough, Texas toast, or thick-cut sandwich bread can make the casserole even better.

Grate your own cheese when possible. Freshly shredded cheese usually melts more smoothly than packaged pre-shredded cheese.

Don’t skip the resting period. Giving the assembled casserole 10–15 minutes before baking helps the bread absorb the egg custard evenly.

Brown the sausage properly. Those browned edges add considerable flavor.

Avoid overbaking the eggs. Once the center has set, remove the casserole from the oven. Excessive baking can make eggs rubbery.

Let it rest after baking. Ten minutes is usually enough for clean, attractive slices.

Make-Ahead Version

This casserole is especially convenient for holiday mornings because you can assemble much of it the night before.

Prepare the sausage and grilled cheese sandwiches.

Arrange everything in your baking dish and pour the egg mixture over the top.

Cover tightly and refrigerate overnight.

The following morning, remove the casserole from the refrigerator while the oven preheats.

Add the final cheese layer and bake as directed.

Because the casserole starts cold, it may require an additional 5–10 minutes of baking time.

Cheese Variations

Cheddar is the classic choice, but there are plenty of delicious alternatives.

Try pepper Jack for a spicy version.

Monterey Jack creates a mild and exceptionally creamy casserole.

Smoked Gouda pairs beautifully with breakfast sausage and gives the dish a deeper smoky flavor.

You can also combine sharp cheddar with American cheese for a flavor reminiscent of classic diner-style grilled cheese.

Sausage Variations

Traditional breakfast sausage gives this casserole its familiar savory flavor, but you can easily customize it.

Try spicy breakfast sausage for extra heat.

Turkey or chicken breakfast sausage can create a slightly lighter version.

Italian sausage can also work, although it changes the flavor profile considerably.

Whatever sausage you choose, cook it completely and drain excess grease before adding it to the casserole.

Add Vegetables

Vegetables can transform this rich casserole into a more colorful breakfast.

Bell peppers, onions, mushrooms, spinach, and broccoli all work well.

However, vegetables containing lots of water should usually be cooked before they’re added.

For example, mushrooms release considerable moisture during cooking. Adding raw mushrooms directly to the casserole can make the egg mixture watery.

Sautéing vegetables first concentrates their flavors and improves the final texture.

Spicy Version

If you enjoy spicy breakfasts, add:

1 diced jalapeño
¼–½ teaspoon crushed red pepper flakes
Pepper Jack cheese
A few dashes of hot sauce

You can also use spicy breakfast sausage instead of regular sausage.

Serve the finished casserole with additional hot sauce for anyone who wants even more heat.

What to Serve With It

Because this casserole is rich and filling, fresh or lighter sides provide a nice contrast.

Serve it with fresh berries, sliced oranges, melon, avocado, roasted potatoes, hash browns, or a simple fruit salad.

For brunch, you can also pair it with pancakes, waffles, muffins, or cinnamon rolls.

A cup of hot coffee or fresh orange juice completes the classic breakfast combination.

Storage and Reheating

Allow leftovers to cool before transferring them to an airtight container.

Store them in the refrigerator for approximately 3–4 days.

Individual portions can be reheated in the microwave for a quick breakfast.

For the best texture, reheat larger portions in a 325°F (165°C) oven until warmed through.

The casserole can also be divided into individual portions before refrigeration, making it convenient for meal-prep breakfasts throughout the week.

Estimated Nutrition

One serving contains approximately:

Calories: 450–550
Protein: 25–30 g
Carbohydrates: 20–30 g
Fat: 30–38 g

These values are estimates and will vary significantly depending on the bread, sausage, cheese, butter, and portion size used.

Final Result

A freshly baked Grilled Cheese Sausage & Egg Breakfast Casserole should have a golden, cheesy top with a soft and savory center packed with sausage, eggs, toasted bread, and pockets of melted cheese.

The grilled cheese pieces are what make this breakfast casserole different from a traditional egg bake. They bring buttery toasted flavor and extra melted cheese into practically every bite, creating a satisfying breakfast that’s especially good for feeding a hungry family or brunch crowd.