The Ultimate Overnight Breakfast Casserole

I remember the first time I hosted a weekend brunch for out of town family, I wanted something comforting and delicious that wouldn’t have me scrambling in the kitchen at the crack of dawn so I decided to try making an overnight breakfast casserole and from the moment I pulled it out of the oven the warm cheesy aroma won everyone over immediately and it quickly became a family staple.

What I love most is that this casserole lets me prep everything the night before and then enjoy a slow morning with coffee and conversation while the oven does the work and it’s hearty enough to feed a crowd yet flexible enough to switch up with different ingredients depending on what I have on hand and who’s coming over and no matter how I make it it always feels like a warm hug on a plate.

Ingredients

Here’s what I use for this recipe. You can always make substitutions if you prefer!

• Breakfast sausage – Adds savory, meaty richness and a flavorful base to the casserole.
• Frozen hash browns – These provide a crispy, starchy layer that soaks up all the goodness.
• Eggs – The glue that binds everything together while adding protein and fluffiness.
• Milk – Helps the eggs stay creamy and tender during baking.
• Sour cream – Adds tang and richness for an ultra-satisfying texture.
• Shredded cheddar cheese – Melts into gooey deliciousness and adds sharpness.
• Green onions – A fresh, vibrant topping that gives a nice crunch and color.
• Salt – Enhances every ingredient in the dish.
• Black pepper – Adds just the right amount of kick.

Tools You’ll Need

• Large skillet – Perfect for browning the sausage evenly and quickly.
• Mixing bowls – I use a couple to combine the egg mixture and prep the rest.
• 9×13-inch baking dish – The ideal size to layer everything without overflowing.
• Whisk – Helps get the egg mixture smooth and well-combined.
• Spatula – Great for layering and smoothing ingredients in the dish.
• Aluminum foil – I use it to cover the casserole overnight and during the initial bake.
• Oven – The final magic-maker that turns it golden, bubbly, and ready to serve.

Instructions

Step 1:

I start by cooking the breakfast sausage in a skillet over medium heat until it’s browned and crumbly and then I set it aside to cool slightly.

Step 2:

Next, I grab a large mixing bowl and whisk together the eggs, milk, sour cream, salt, and black pepper until the mixture is nice and smooth.

Step 3:

In a greased 9×13 baking dish, I layer half of the hash browns at the bottom followed by half the sausage and a generous sprinkle of cheddar cheese.

Step 4:

Then I repeat the layers with the remaining hash browns, sausage, and more cheese to create that stacked, hearty goodness.

Step 5:

Now I pour the egg mixture evenly over the entire dish making sure it seeps down through the layers and covers everything.

Step 6:

I cover it with foil and let it sit in the fridge overnight so the flavors can mingle and the hash browns can soak in the egg mixture.

Step 7:

In the morning, I preheat the oven to 350°F and bake the casserole covered for 45 minutes.

Step 8:

After that, I remove the foil and bake for another 20-25 minutes until the top is golden and bubbly and the center is fully set.

Step 9:

Just before serving, I sprinkle freshly chopped green onions on top for that extra fresh finish.

Tips

If you want to make it extra creamy, I suggest adding a handful of shredded mozzarella in addition to cheddar. I’ve also swapped the sausage for bacon or even diced ham with great results. Sometimes I throw in sautéed bell peppers or spinach to sneak in some veggies. And don’t skip the overnight step—it really does make a difference in texture and flavor!

Ways to Serve

I love serving this with a fresh fruit salad or buttery toast on the side. It’s also amazing with a drizzle of hot sauce or a dollop of salsa. For a bigger spread, I sometimes pair it with muffins or cinnamon rolls for a sweet contrast.

Frequently Asked Questions

Can I freeze The Ultimate Overnight Breakfast Casserole?

Yes! I recommend baking it first then letting it cool completely before wrapping it tightly and freezing for up to 2 months.

Can I make The Ultimate Overnight Breakfast Casserole vegetarian?

Absolutely. Swap the sausage with sautéed mushrooms, spinach, and bell peppers for a tasty meat-free version.

How long can The Ultimate Overnight Breakfast Casserole sit in the fridge before baking?

I usually prep it up to 12 hours in advance. You can stretch it to 24 hours, but don’t go beyond that for food safety reasons.

See You in the Kitchen

I hope you give this overnight breakfast casserole a try! It’s become one of my go-to recipes for lazy weekends and holiday brunches. I’d love to hear how it turns out for you share your results or let me know how you made it your own!

Happy Cooking!

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