If you’re craving a hearty, hands-off morning meal that’ll feed a crowd and leave your kitchen smelling like pure comfort, the Overnight Slow Cooker Breakfast Casserole is your new breakfast hero. This recipe is the ultimate backstage pass to waking up to layers of savory sausage, colorful peppers, fluffy eggs, and melted cheddar — all without an ounce of morning effort. Perfect for busy family mornings, lazy brunches with friends, or holiday gatherings, it’s a customizable classic that you can make your own. One dreamy casserole, endless cozy mornings!

Overnight Slow Cooker Breakfast Casserole Recipe - Recipe Image

Ingredients You’ll Need

The beauty of the Overnight Slow Cooker Breakfast Casserole is its simplicity — every ingredient pulls its weight for taste, texture, or pops of color. Let’s break down why you’ll love each player in this all-in-one breakfast staple.

Breakfast sausage: Savory and rich, cooked sausage gives each bite heartiness and irresistible spiced flavor.
Onion: Diced onion adds sweetness and depth, lending a homey aroma as it cooks low and slow.
Red bell pepper: This pepper brings sweetness and a vibrant red hue that brightens the entire casserole.
Green bell pepper: Slightly earthy and fresh, green pepper balances the flavors and adds more color.
Frozen hash browns (shredded or diced): They form a delicious, tender potato layer that soaks up all the goodness on top.
Shredded cheddar cheese: Gooey and sharp, cheddar melts into the nooks and crannies for ultimate comfort.
Large eggs: Eggs create the fluffy, creamy base that binds all the tasty layers together.
Milk: Adding milk makes the eggs extra light and custardy as they cook overnight.
Garlic powder: Just a touch boosts the savory flavors for a subtle garlicky backdrop.
Salt: Essential for bringing out every flavor in this layered masterpiece.
Black pepper: Fresh black pepper gives a gentle kick and warmth to balance the richness.
Nonstick cooking spray: Nobody wants stuck-on eggs! A generous spray means easy serving and cleanup.

How to Make Overnight Slow Cooker Breakfast Casserole

Step 1: Prep Your Slow Cooker

Start by giving your slow cooker insert a generous coating of nonstick cooking spray. This small step is so important — not only does it mean cleanup is a breeze, but it also helps every cheesy, potatoey bite come out cleanly when serving.

Step 2: Layer the Potatoes, Sausage, Peppers, and Cheese

Begin by adding half of the frozen hash browns, spreading them evenly on the bottom. Top with half of your cooked sausage, half each of the diced onions and bell peppers, and then half the shredded cheddar. Layering ensures you get all the goodness in every scoop! Repeat with the rest of each ingredient for a double-stacked effect.

Step 3: Mix the Egg Mixture

In a large bowl, whisk together the eggs, milk, garlic powder, salt, and pepper until well combined. The milk will make your eggs extra fluffy, and the seasonings infuse every nook with flavor. Your arm workout here really pays off with a perfectly uniform custard.

Step 4: Pour and Cook

Carefully pour the egg mixture over your layered ingredients in the slow cooker, making sure to cover everything evenly. Pop on the lid, set your slow cooker to low for 7–8 hours (overnight) or high for 3–4 hours. As it cooks, your kitchen will start to smell like breakfast heaven, and you can go about your night or morning routine with zero stress.

Step 5: Let It Rest and Serve

Once the eggs are completely set and the top is slightly golden, turn off the heat and let the Overnight Slow Cooker Breakfast Casserole rest (lid off) for about 10 minutes. This allows the layers to settle and makes serving so much easier. Slice, scoop, and enjoy the magic!

How to Serve Overnight Slow Cooker Breakfast Casserole

Garnishes

Sprinkle your finished casserole with fresh herbs like chives, parsley, or green onions for a burst of color and brightness. A dollop of sour cream or a spoonful of salsa on top brings a cool tang and ties all the flavors together beautifully.

Side Dishes

Pair your Overnight Slow Cooker Breakfast Casserole with a simple fruit salad, buttery toast, or even a light arugula salad for a brunch-worthy spread. If you’re cooking for a crowd, offer some crispy bacon or a basket of muffins on the side to round out the meal.

Creative Ways to Present

For a special gathering, cut the casserole into neat squares and serve them on a platter, garnished with fresh herbs and a colorful side. You can also scoop individual portions into small bowls for grab-and-go mornings or layer them in mini mason jars for a fun, portable breakfast twist.

Make Ahead and Storage

Storing Leftovers

Leftovers of the Overnight Slow Cooker Breakfast Casserole are a lifesaver for busy weekdays! Simply transfer cooled portions into airtight containers and refrigerate for up to 4 days. Each bite reheats beautifully, keeping its tender texture and rich flavor without getting mushy.

Freezing

If you want to get ahead, this casserole is freezer-friendly. Allow it to cool completely, then cut into single servings and wrap well in plastic wrap or foil before storing in freezer bags. Label them with the date, and you’ll have ready-to-reheat breakfasts for up to 2 months.

Reheating

To reheat, just pop individual portions in the microwave for about 1–2 minutes, or warm larger portions in the oven at 350°F until heated through. For best texture, sprinkle a tiny bit of water over the top before microwaving, which keeps everything fluffy and moist.

FAQs

Can I use bacon or ham instead of sausage?

Absolutely! Bacon or diced ham work beautifully as a substitute for sausage. You can even do a blend for extra savory flavor — just be sure all meats are cooked before layering them into the casserole.

What kind of slow cooker should I use?

Any 6-quart oval slow cooker will work best for this recipe, as it provides enough surface area for even cooking. If you use a smaller model, keep an eye on cooking time and check for doneness so the eggs set properly.

Can I add extra vegetables or make it vegetarian?

Of course! Spinach, mushrooms, or even zucchini are excellent veggie additions. For a vegetarian version, simply skip the meat or use your favorite plant-based sausage.

How do I know when the casserole is done?

You’ll know it’s ready when the eggs are fully set and no longer jiggly in the center. The top will look puffy and just lightly golden. If in doubt, insert a knife in the center — it should come out clean.

Can I prepare this ahead and cook later?

Yes, you can assemble all the layers in the slow cooker insert, cover, and refrigerate the night before. In the morning, just let it sit at room temperature for about 30 minutes and then start the cooking process. Easy steaming mornings ahead!

Final Thoughts

If you love waking up to a warm, mouthwatering breakfast without lifting a finger, treat yourself and your loved ones to the Overnight Slow Cooker Breakfast Casserole. With adaptable ingredients and practically effortless prep, it’s the recipe you’ll want on repeat for weekends, holidays, or any time you need breakfast to feel a little extra special. Give it a try — mornings just got a serious glow-up!