The Best Overnight Sausage Breakfast Casserole (Easy & Make-Ahead!)

The Overnight Breakfast Casserole That Makes Christmas Morning Magical

Christmas morning is pure, unadulterated chaos. There’s a blizzard of wrapping paper, squeals of joy, and a desperate, frantic search for batteries. Amidst this beautiful bedlam, a question arises: “What’s for breakfast?” If the thought of whipping up a big meal in the middle of it all makes you want to crawl back into bed, you’re in the right place. These are the Christmas morning recipes that will save your sanity, starting with this incredible Overnight Sausage and Hash Brown Breakfast Casserole.

This is your golden ticket to a stress-free, delicious Christmas morning. You do all the work on Christmas Eve when the house is quiet, and then on the big day, you simply slide it into the oven. You get to sip your coffee and actually watch your family open presents, all while a hearty, cheesy, savory breakfast bakes itself. You’ll look like a superhero, and no one needs to know how easy it was.

Why This Casserole is a Certified Holiday Winner

The number one reason this recipe is a gift from the heavens is that it’s an overnight, make-ahead masterpiece. Seriously, you assemble it the night before, pop it in the fridge, and forget about it. It’s the ultimate gift you can give your future, slightly-less-caffeinated self.

But convenience aside, this casserole is just plain delicious. It’s a hearty, savory powerhouse packed with layers of crispy hash browns, savory breakfast sausage, fluffy eggs, and a glorious blanket of melted cheese. It’s a complete, satisfying meal in one dish that will keep everyone fueled up for a full day of festive fun.

The Simple, Hearty Ingredient Lineup

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You don’t need anything fancy for this crowd-pleaser. Just classic, delicious breakfast staples.

• 1 lb (450g) Breakfast Sausage: Pork, turkey, or even a spicy Italian sausage would be great here.
• 1 small Yellow Onion: Finely chopped.
• 1 Bell Pepper (any color): Chopped. Red or green adds a nice festive touch.
• 1 package (30 oz or about 850g) Frozen Shredded Hash Browns: No need to thaw them! This is the easy button.
• 10 Large Eggs: The heart of our custardy filling.
• 2 cups (480ml) Milk: Whole milk will be the creamiest, but any kind works.
• 1 tsp Dry Mustard Powder: This is a secret ingredient that enhances the cheesy flavor!
• 1 tsp Salt: Or to taste.
• ½ tsp Black Pepper:
• 2 cups (about 8 oz or 225g) Shredded Cheddar Cheese: Or a blend of cheddar and Monterey Jack.

Tools & Kitchen Gadgets Used

This is a straightforward recipe that doesn’t require a ton of special equipment.

• 9×13 inch Casserole or Baking Dish: The perfect size for a crowd-pleasing casserole.
• Large Skillet: For browning the sausage and veggies.
• Large Mixing Bowl: For whisking up the egg custard.
• Whisk: To ensure your egg mixture is perfectly smooth and aerated.
• Spatula or Wooden Spoon: For breaking up the sausage.

Step-by-Step Guide to a Flawless Christmas Breakfast

This process is broken into two super simple parts: a little bit of prep on Christmas Eve, and a hands-off bake on Christmas morning.

H3: The Night Before (Your 20-Minute Prep)

1. Brown the Sausage and Veggies: In your large skillet over medium-high heat, cook the breakfast sausage, breaking it up with your spatula, until it’s no longer pink. Add the chopped onion and bell pepper and continue to cook for another 5-7 minutes, until the vegetables have softened.
2. Drain It Well: This is a crucial step! Drain all the excess grease from the sausage and vegetable mixture. A greasy casserole is a soggy casserole, and nobody wants that.
3. Start Layering: Generously grease your 9×13 inch baking dish. Spread the frozen hash browns in an even layer across the bottom.
4. Keep Layering: Sprinkle the cooked sausage and vegetable mixture evenly over the hash browns. Top this with about 1 ½ cups of the shredded cheese, reserving the last ½ cup for the morning.
5. Make the Custard: In your large mixing bowl, whisk the 10 eggs until they are frothy. Add the milk, dry mustard powder, salt, and pepper, and whisk vigorously until everything is smooth and well-combined.
6. Pour and Soak: Pour the egg mixture as evenly as you can over all the layers in the baking dish.
7. Tuck It In for the Night: Cover the dish tightly with plastic wrap or foil and refrigerate overnight, or for at least 6-8 hours.

H3: Christmas Morning (The Easiest Part)

1. Preheat & Rest: In the morning, preheat your oven to 375°F (190°C). Remove the casserole from the fridge and let it sit on the counter for about 20-30 minutes to take the chill off.
2. Top with More Cheese: Uncover the casserole and sprinkle the remaining ½ cup of shredded cheese over the top.
3. Bake Until Golden: Bake, uncovered, for 50-60 minutes. The casserole is done when the edges are bubbly, the top is golden brown, and a knife inserted into the center comes out clean.
4. Let It Rest: Let the casserole rest for 10 minutes before slicing and serving. This allows the custard to set up, making it easier to serve clean slices.

Calories & Nutritional Info

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Here’s an estimate per serving, assuming the casserole is cut into 10 hearty portions.

• Calories: Approximately 420 kcal
• Fat: 28g
• Carbohydrates: 18g
• Protein: 25g

(Disclaimer: This is just an estimate. The actual values will depend on the type of sausage, cheese, and milk you use.)

Common Mistakes to Avoid (Don’t Sabotage Your Breakfast!)

Follow these tips for a perfect casserole every single time.

1. Forgetting to Drain the Sausage: I’m saying it again because it’s that important. A pool of grease at the bottom of your casserole is a culinary tragedy. Drain the sausage and veggies thoroughly after cooking.
2. Using Thawed Hash Browns (Without Squeezing): If you use thawed hash browns or fresh grated potatoes, you must squeeze out as much moisture as possible with a clean kitchen towel. Excess water will lead to a soggy bottom layer. Using them frozen is the easiest, foolproof method.
3. Underbaking: A jiggly center means you’re about to serve raw eggs. The casserole needs to be fully set in the middle. The knife test is your best friend here. If it’s getting too brown on top before the center is done, just lightly tent it with foil.
4. Skipping the Rest: Cutting into it immediately will cause it to fall apart. That 10-minute rest allows everything to settle and firm up, so you can serve beautiful, clean squares.

Variations & Customizations

Think of this recipe as a blank canvas for your breakfast dreams.

• Make it Vegetarian: Swap the pork sausage for a plant-based sausage crumble (like Beyond or Impossible). To up the veggie content, add 8 oz of sautéed mushrooms and a few handfuls of fresh spinach to the vegetable mix.
• Spicy Southwest Casserole: Use chorizo instead of breakfast sausage, add a 4 oz can of diced green chiles to the mix, and use a shredded Pepper Jack or Colby Jack cheese blend. Serve with a side of salsa and sour cream.
• Bacon and Ham Lovers: Not a sausage fan? Use 1 pound of cooked, crumbled bacon or 2 cups of diced ham instead. Both are fantastic.

FAQ: Your Christmas Casserole Questions, Answered

Let’s get you ready for breakfast success.

1. Can I use tater tots instead of shredded hash browns?

Absolutely! A layer of frozen tater tots on the bottom makes for a delicious, crispy base. Just follow the recipe as written, substituting the hash browns with tots.

2. Why is my breakfast casserole watery or soggy?

This is usually caused by excess moisture. The main culprits are not draining the sausage grease or using vegetables with high water content (like mushrooms or spinach) without pre-cooking them to release their moisture.

3. Can I assemble and bake this on the same day?

You can, but the texture is much better if you let it soak overnight. The hash browns soften, and the egg has time to fully saturate everything. If you must bake it the same day, let it soak for at least 2 hours.

4. How do I know when it’s done?

The top will be golden and bubbly, and the center should not jiggle when you gently shake the pan. A knife inserted in the center should come out clean, with no liquid egg on it.

5. Can I make this casserole gluten-free?

Yes! The recipe is naturally gluten-free as long as you ensure your breakfast sausage doesn’t contain any gluten fillers. Just double-check the labels.

6. How do I store and reheat leftovers?

Store leftovers covered in the refrigerator for up to 3-4 days. You can reheat individual slices in the microwave, or reheat the entire casserole in a 350°F (175°C) oven until warmed through.

7. Can I freeze this breakfast casserole?

Yes, it freezes well. You can freeze it baked or unbaked. For best results, bake it first, let it cool completely, then wrap it tightly and freeze for up to 3 months. Thaw it overnight in the fridge before reheating.

Final Thoughts

And there you have it—a warm, hearty, and unbelievably easy breakfast that will start your Christmas day off on the most delicious note possible. This recipe isn’t just about feeding your family; it’s about giving yourself the gift of a relaxed, stress-free morning. Go on, claim your title as the Christmas Morning MVP. You deserve it.