Overnight Breakfast Casserole

Looking for a make-ahead breakfast that’s hearty, satisfying, and feeds a crowd? This Overnight Breakfast Casserole is your perfect solution. Loaded with eggs, veggies, bread, and savory sausage or beef, this dish is assembled the night before and baked in the morning for a stress-free breakfast. Whether it’s for a holiday morning, brunch with friends, or just a cozy weekend, this casserole will become your new go-to recipe.

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Why You’ll Love This Recipe
Make-Ahead Convenience – Assemble it the night before and bake it fresh in the morning.
Feeds a Crowd – Perfect for family gatherings, holidays, or meal prep.
Customizable – Use your favorite veggies, meats, and cheeses.
Comforting & Filling – A warm and satisfying start to the day.
Minimal Morning Effort – Just pop it in the oven and relax.

Ingredients You’ll Need

For the Casserole Base:
8 slices of bread (day-old or slightly toasted), cubed
1 lb ground beef or breakfast sausage
1 cup shredded cheddar cheese
1 cup shredded mozzarella cheese
1 medium bell pepper, chopped
1 small onion, finely chopped
1 cup fresh spinach, chopped (optional)
½ tsp salt
½ tsp black pepper
½ tsp garlic powder
½ tsp paprika

For the Egg Mixture:
8 large eggs
2 cups milk (whole or 2%)
½ tsp Dijon mustard (adds subtle flavor)
¼ tsp ground nutmeg (optional, for a touch of warmth)

For Garnish & Serving:
2 tbsp chopped chives or green onions
Hot sauce or ketchup (optional)
Fresh fruit or juice on the side

Tools You’ll Need

9×13-inch baking dish
Large skillet
Mixing bowls
Whisk
Aluminum foil
Measuring cups and spoons

Step-by-Step Instructions

Step 1: Prepare the Ingredients

1. Lightly grease a 9×13-inch baking dish with oil or butter.
2. Cut the bread into 1-inch cubes and set aside.
3. In a large skillet over medium heat, cook the ground beef or sausage until browned. Break it up with a spoon as it cooks. Drain excess fat if needed.
4. Add chopped onion and bell pepper to the skillet and cook for 3-4 minutes until softened. Add the spinach (if using) and stir until wilted. Season with salt, pepper, garlic powder, and paprika.

Step 2: Assemble the Casserole
5. Spread the bread cubes evenly in the prepared baking dish.
6. Spoon the cooked meat and veggie mixture over the bread.
7. Sprinkle both cheddar and mozzarella cheese evenly on top.

Step 3: Mix the Egg Mixture
8. In a large bowl, whisk together eggs, milk, Dijon mustard, and nutmeg until fully combined.
9. Slowly pour the egg mixture over the layered casserole, making sure all the bread is moistened.

Step 4: Refrigerate Overnight
10. Cover the baking dish with aluminum foil and refrigerate for at least 6 hours or overnight. This allows the bread to soak up all the flavors.

Step 5: Bake in the Morning
11. Preheat your oven to 350°F (175°C).
12. Remove the casserole from the fridge and let it sit at room temperature for 20 minutes while the oven heats.
13. Bake, covered with foil, for 30 minutes.
14. Remove the foil and continue baking for another 15–20 minutes until the top is golden and the center is set (a knife inserted should come out clean).

Step 6: Garnish & Serve
15. Let the casserole rest for 5–10 minutes before slicing.
16. Sprinkle with chopped chives or green onions.
17. Serve with hot sauce, ketchup, or fresh fruit on the side.

Tips for the Best Overnight Casserole
Use Sturdy Bread – Day-old bread or slightly toasted bread holds up best and won’t get soggy.
Don’t Skip the Resting Time – Letting the casserole sit before baking ensures even cooking and helps it firm up.
Mix and Match Ingredients – Swap veggies, try different cheeses, or use turkey sausage for variety.
Bake Covered First – This helps the casserole cook through without over-browning the top.
Let It Cool Slightly – This helps with cleaner slices and better flavor.

Serving Suggestions
Fresh Fruit Salad – Brighten the plate with melon, berries, or citrus.
Breakfast Potatoes – Crispy hash browns or roasted potatoes complement the casserole.
Simple Side Salad – A light green salad adds freshness and balance.
Fresh Juice or Coffee – Start the morning with your favorite drink.

How to Store & Reheat

Storing:
Refrigerate: Store leftovers in an airtight container for up to 3 days.
Freeze: Wrap tightly and freeze individual portions for up to 2 months.

Reheating:
Oven: Cover with foil and warm in a 350°F oven for 15–20 minutes.
Microwave: Heat slices on medium power for 1–2 minutes until hot.

Frequently Asked Questions

1. Can I make this without meat?
Yes! Just increase the veggies or add a plant-based meat alternative.

2. What kind of bread works best?
Use hearty white bread, sourdough, or whole wheat. Avoid very soft sandwich bread.

3. Can I prepare this the same morning?
Yes, but let it soak for at least 30 minutes before baking if you’re short on time.

4. Can I use non-dairy milk?
Absolutely. Almond milk or oat milk can work well, though the texture may vary slightly.

Final Thoughts
This Overnight Breakfast Casserole is everything you want in a make-ahead morning meal—rich, savory, cheesy, and endlessly customizable. It’s perfect for holidays, brunches, or even meal prep for busy weeks. The best part? All the work is done the night before, so your morning can be calm, delicious, and filled with the smell of breakfast baking in the oven.

Try it out and let me know how your version turns out! Don’t forget to leave a review and share your breakfast creations.

Preparation Time: 20 minutes
Cooking Time: 50 minutes
Cuisine: American

Nutritional Information (Per Serving):
Calories: 360 | Protein: 21g | Carbohydrates: 18g | Fat: 23g | Fiber: 2g | Sodium: 480mg

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