Easy Make-Ahead Breakfast Casserole Recipe

This Easy Make-Ahead Breakfast Casserole is a game-changer for busy mornings, combining creamy eggs, savory sausage, and golden potatoes in one hearty dish.

With just 40 minutes of prep and 45 minutes of baking, you’ll have a flavorful, crowd-pleasing meal ready to enjoy or store for later. The melty cheese and crispy edges add a satisfying contrast, while the blend of herbs infuses every bite with warmth and comfort.

Perfect for weekend brunches or weekday grab-and-go mornings, this casserole is as versatile as it is delicious. The rich, savory flavors and fluffy texture make it a family favorite, and the make-ahead convenience ensures you’re always prepared. Whether served fresh from the oven or reheated, it’s a breakfast that feels indulgent yet effortless.

Ingredients for Easy Make-Ahead Breakfast Casserole

• 12 large eggs
• ¾ cup (6 fl oz/180 ml) whole milk
• ½ cup (4 fl oz/120 ml) heavy cream
• 1 pound (16 oz/450 g) uncased ground sausage (cooked; substitute with turkey sausage or bacon if preferred)
• 2 cups (7 oz/200 g) shredded sharp cheddar cheese (or any cheese of your choice)
• 1 cup (8 oz/225 g) defrosted and drained frozen spinach (or substitute with other veggies like bell peppers or mushrooms)
• ½ medium onion, diced
• 2 cloves garlic, crushed
• 1 teaspoon salt
• 1 teaspoon black pepper
• 4 cups (6 oz/170 g) cubed, stale bread (use day-old bread for best results)

Step-by-Step Instructions

1. Preheat the oven to 375°F (190°C). Butter a 9×13-inch (23×33 cm) baking dish and set aside.
2. In a large bowl, whisk together the eggs, milk, and cream until well beaten.
3. Stir in the cooked sausage, cheese, spinach, onion, garlic, salt, and pepper until evenly combined.
4. Add the bread cubes and mix until they are well coated with the egg mixture.
5. Transfer the mixture to the prepared baking dish. Let it sit on the counter for at least 30 minutes (or overnight in the fridge) to allow the bread to absorb the liquid. Press down the bread to ensure it’s submerged.
6. Bake for 45 minutes, or until the casserole is slightly puffed, firm, and a knife inserted in the center comes out clean.
7. Let the dish rest for 10 minutes before serving. Store leftovers in the refrigerator for up to 3 days. Reheat in a 300°F (150°C) oven for 15 minutes or in the microwave.

Make It Your Own: Recipe Variations

This breakfast casserole is super versatile! Swap the sausage for cooked bacon, ham, or even crumbled tofu for a vegetarian twist. Not a fan of spinach? Try broccoli, bell peppers, or mushrooms instead.

For a cheesy upgrade, mix in Monterey Jack or pepper jack cheese. You can also use gluten-free bread cubes if needed—just make sure they’re stale for the best texture.

Perfect Pairings: Serving Suggestions

Serve this hearty casserole with a side of fresh fruit, avocado slices, or a simple green salad for a balanced meal. A dollop of salsa or hot sauce adds a zesty kick, while a drizzle of hollandaise sauce makes it feel extra indulgent. Don’t forget a warm cup of coffee or orange juice to complete your breakfast spread!

Plan Ahead: Storage and Reheating Tips

This casserole is a great make-ahead dish! After baking, let it cool completely, then store it in the fridge for up to 3 days. To reheat, cover it with foil and warm in a 300°F (150°C) oven for 15 minutes, or microwave individual portions for 1-2 minutes.

For longer storage, freeze slices in airtight containers for up to 2 months—just thaw overnight in the fridge before reheating.

Time-Saving Hacks for Busy Mornings

Save time by prepping ingredients the night before! Cook the sausage, dice the onion, and cube the bread ahead of time. You can even assemble the entire casserole and let it soak overnight in the fridge—just pop it in the oven in the morning. If you’re short on time, use pre-shredded cheese and frozen diced onions for extra convenience.

Essential Equipment for Success

You’ll need a 9×13-inch (23×33 cm) baking dish for this recipe—glass or ceramic works best for even cooking. A large mixing bowl and whisk are essential for combining the ingredients, and a sharp knife or kitchen shears will make cubing the bread a breeze. Don’t forget a spatula for pressing down the bread cubes to ensure they soak up all the delicious liquid!