Overnight Breakfast Casserole (Easy Make-Ahead Holiday Breakfast)

If you’re looking for a comforting, make-ahead breakfast that your whole family will love, this Overnight Breakfast Casserole is the perfect choice. It’s warm, cheesy, easy to assemble, and ideal for holidays, brunch gatherings, or busy mornings when you want something hearty without the work.

In my home, this casserole has become a cherished tradition. Every Christmas morning and Mother’s Day, I prepare it the night before, pop it into the oven while we open gifts. It’s simple, satisfying, and makes the morning feel extra special. Sometimes we also add mimosas, fresh fruit, and pastries to turn it into a full brunch spread.

One thing I love about this recipe is how customizable it is. I usually make one with ham or bacon (or both!) and a second vegetarian version for my daughter. It’s flexible, dependable, and always a crowd favorite.

Why You’ll Love This Breakfast Casserole

• Make-ahead friendly — prepare everything the night before.

• Perfect for holidays & guests — feeds a crowd with minimal effort.

• Customizable — add veggies, switch the meat, or keep it vegetarian.

• Family-friendly — savory, cheesy, and always a hit.

• Budget-friendly ingredients — simple, pantry-friendly staples.

Ingredients You’ll Need

• 8 frozen hashbrown patties (thawed)

• 4 cups shredded cheddar cheese

• Fully cooked ham or bacon (or half and half)

• 7 large eggs

• 1 cup milk

• ½ teaspoon salt

• ½ teaspoon ground mustard

The ground mustard doesn’t make the casserole taste like mustard — it simply adds depth and enhances the cheesy flavor.

How to Make Overnight Breakfast Casserole

1. Prepare the pan
   Grease a 9×13 baking dish and lay the thawed hashbrown patties in a single layer.

2. Add toppings
   Sprinkle shredded cheddar evenly over the hashbrowns. Add your ham, bacon, or both.

3. Mix the egg mixture
   Whisk eggs, milk, salt, and ground mustard together. Pour evenly over the casserole.

4. Cover and refrigerate
   Let the casserole chill overnight (or at least a few hours).

5. Bake

   • 1 hour covered

   • 10–15 minutes uncovered until golden and bubbly

The center should be set before removing from the oven.

Breakfast Casserole Variations

Try one of these fun twists:

• Vegetarian: Skip the meat and add sautéed bell peppers, onions, spinach, or mushrooms.

• Southwest style: Add diced green chiles, pepper jack cheese, and cooked chorizo.

• Meat lovers: Mix bacon, sausage, and ham.

• Lighter version: Use reduced-fat cheese and swap hashbrowns for shredded sweet potatoes.

• Kid-friendly: Add mini ham cubes and a sprinkle of mild cheddar on top.

What to Serve with Breakfast Casserole

• Fresh fruit or fruit salad

• Cinnamon rolls or pastries

• Yogurt parfaits

• Warm biscuits

• Mimosas or fresh orange juice

How to Store & Reheat

• Refrigerate: Store leftovers in an airtight container for 3–4 days.

• Freeze: Freeze individual slices for up to 2 months.

• Reheat: Warm in the microwave or reheat in the oven at 325°F until heated through.

FAQ

Can I bake this without refrigerating overnight?

Yes! Overnight is best for flavor, but you can bake immediately — just add 5–10 extra minutes.

Can I use shredded hashbrowns instead of patties?

Absolutely. Spread them evenly across the pan before adding cheese and meat.

Can I make a dairy-free version?

Yes, use dairy-free cheese and unsweetened almond milk.

Can I double this recipe?

Yes, but use two separate pans for even cooking.

❤️ A Family Tradition

This overnight Breakfast Casserole has become a recipe my family looks forward to every year. It’s comforting, flavorful, and makes holiday mornings feel warm and memorable. Whether you’re serving it for Christmas, Mother’s Day, or a casual brunch, it’s a recipe you’ll come back to again and again.