Name: Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe
Prep time: 10 min
Cook time: 1 h 40 min
Total time: 1 h 50 min
Cuisine: American
Ingredients: 3 Tablespoons salted butter; 3 Tablespoons all purpose flour; 2 cups milk (2%); 1 teaspoon salt; ½ teaspoon black pepper; ½ teaspoon garlic powder; 24 ounces fresh broccoli pieces (about 8 cups); 1.5 cups shredded cheddar cheese; 1 cup fried onions

If you’ve been hunting for a comforting, no-fuss side dish that feels like a warm hug on a plate, then you’re going to flip when you try this Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe. I absolutely love how this combo of tender broccoli, creamy cheddar sauce, and crispy fried onions comes together with hardly any hands-on time. When I first tried it, I couldn’t believe how perfectly the slow cooker pulled all the flavors together – rich, cheesy, and crunchy all at once. Trust me, you’ll want to keep this one in your recipe rotation!

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Why You’ll Love This Recipe

Hands-off Cooking: The slow cooker does all the work while you go about your day.
Comfort Food at Its Best: Creamy, cheesy, and topped with that irresistible crunch of fried onions.
Family-Friendly: My whole family goes crazy for this casserole – even the picky eaters!
Flexible Ingredients: Easy swaps let you personalize based on preferences or what you have on hand.

A close-up of a silver fork holding a small piece of cooked broccoli with bits of light orange shrimp and melted light yellow cheese. Below, a white plate holds a pile of similar broccoli pieces mixed with shrimp and cheese. The background shows a white marbled surface with some green garnish and a white bowl filled with more broccoli and shrimp in a soft focus. Photo taken with an iphone --ar 4:5 --v 7

Ingredients You’ll Need

Every ingredient here plays a role in creating that luscious texture and classic flavor. Plus, these pantry staples make this Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe super easy to gather before you get started.

Salted Butter: I find salted butter adds just the right touch of richness that melds everything together smoothly.
All-purpose Flour: This is your thickening agent for the creamy sauce—whisk well to avoid lumps!
Milk (2% works great): It creates a velvety consistency; whole milk is richer if you want to treat yourself.
Salt: Balances the flavors—don’t skip, but taste before adding more.
Black Pepper: Adds a subtle kick; freshly ground is always best.
Garlic Powder: A quick way to boost flavor without chopping fresh garlic.
Fresh Broccoli Pieces: About 8 cups—this is the star vegetable, chopped bite-sized for even cooking.
Shredded Cheddar Cheese: Sharp cheddar brings a zing, but mild works too if you prefer a creamier flavor.
Fried Onions: The perfect crispy topping that contrasts the creamy casserole underneath.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

One of the things I love most about the Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe is how easy it is to tweak. I often mix things up depending on the season or what’s in my fridge. Feel free to make this your own!

Cheese Swap: I’ve tried sharp white cheddar or a combo of mild cheddar and Parmesan for an extra flavor punch—both are winners in my book.
Veggie Mix: Sometimes I swap half the broccoli for cauliflower to add a different texture and mild sweetness.
Topping Alternatives: While fried onions are classic, substituting crushed Ritz crackers or even crispy bacon bits turns out delicious and exciting.
Cream Soup Swap: For faster prep, some days I like adding a can of cream of mushroom or cream of chicken soup to the mix for a different twist.

How to Make Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe

Step 1: Make a Smooth, Creamy Sauce

Start by melting your salted butter over medium heat in a small saucepan. Once melted, whisk in the flour and let it cook for 2-3 minutes. This step is key to getting rid of that raw flour taste and starting to build your sauce’s body. Then, slowly whisk in the milk until the mixture is smooth — no lumps! Season with salt, pepper, and garlic powder. Keep stirring frequently and let it thicken to a creamy gravy consistency. I always remind myself not to rush this step; your patience here makes a silky sauce that coats the broccoli beautifully.

Step 2: Layer and Cook in the Slow Cooker

Spray the inside of your 6-quart slow cooker with some cooking spray to keep things from sticking. Pour in the fresh broccoli pieces and pour the sauce on top. Gently stir everything so the broccoli gets coated—but don’t over-stir or you risk breaking those vibrant florets. Cover, then cook on HIGH for 1 hour or LOW for 2 hours. After that, give it a stir, replace the lid, and cook for another 30 minutes or until the broccoli is fork-tender. Everyone’s slow cooker heats a bit differently, so it’s a good idea to check in early to prevent overcooking.

Step 3: Add Cheese and Crunchy Topping

Once the broccoli is just right, sprinkle in your shredded cheddar cheese, stir it in gently until it melts into the sauce. Then top with the fried onions for that signature crunch. Cook uncovered for another 10 minutes to let the cheese melt and the onions crisp up a bit. When I make this for guests, this last step is the one that always gets compliments — everyone loves the contrast of textures!

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Pro Tips for Making Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe

Whisking is Key: Always whisk the flour into melted butter well and cook it briefly to avoid a gritty roux.
Check for Doneness: Since slow cookers vary, start checking broccoli tenderness around the earlier cooking times to prevent mushiness.
Keep it Crispy: Add the fried onions only at the end and cook uncovered to maintain their crunch instead of sogginess.
Use Fresh Broccoli: Fresh florets give the best texture — if using frozen, thaw and drain thoroughly to avoid watery casserole.

How to Serve Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe

The dish shows a white plate filled with roasted broccoli pieces covered in melted cheese. The broccoli is bright green with some browned, crispy edges from roasting, and the cheese is creamy yellow with a slightly golden, melted texture layered unevenly over the broccoli. In the background, there is another white bowl with more broccoli and a green cloth next to a bunch of fresh parsley, all set on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Garnishes

I love finishing this casserole with a sprinkle of fresh parsley or chives—it adds a pop of color and light freshness that brightens the creamy richness. Sometimes I’ll even add a squeeze of fresh lemon juice right before serving to balance the richness if I’m feeling fancy.

Side Dishes

This Slow Cooker Broccoli Casserole is a perfect side for hearty mains like roasted chicken, meatloaf, or pork chops. Whenever I’m pressed for time, I pair it with crusty bread and a simple green salad for an easy, crowd-pleasing meal.

Creative Ways to Present

For special occasions, I’ve served this casserole in individual ramekins topped with extra fried onions and a sprinkle of Parmesan, which makes it feel extra special and festive. You can also layer the casserole in a beautiful baking dish for family-style serving that invites everyone to dig in.

Make Ahead and Storage

Storing Leftovers

When I have leftovers, I cover them tightly with plastic wrap or transfer the casserole to an airtight container and store it in the fridge. It keeps well for up to 4 days, and I find the flavors even meld a bit more, which is a nice bonus.

Freezing

I’ve frozen this casserole a couple of times by letting it cool completely, portioning into freezer-safe containers, and sealing tightly. When you’re ready to enjoy, thaw overnight in the fridge and reheat gently in the oven—this keeps the texture much better than microwaving straight from frozen.

Reheating

To reheat, I prefer warming it in a 350°F oven covered with foil to prevent drying out—about 20 minutes or until warmed through. If you want to revive the crispy onion topping, add fresh fried onions just before serving.

FAQs

Can I use frozen broccoli for this Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe?

Yes! You can use frozen broccoli, but make sure to thaw it completely and drain any excess water before adding it to the slow cooker. This helps prevent the casserole from becoming too watery.
What type of cheddar cheese works best?

Sharp cheddar gives the casserole a nice tang and depth, but if you prefer a milder taste, feel free to use mild cheddar. Mixing in Parmesan can also add extra flavor complexity.
Can I prepare the casserole in advance?

Absolutely! You can assemble the casserole ingredients in the slow cooker insert, cover, and chill it overnight in the fridge. Just add the fried onions and cheese before cooking the next day.
How do I prevent the fried onions from getting soggy?

Add the fried onions at the very end of cooking and cook uncovered for just 10 minutes. Avoid covering the slow cooker after adding them to keep their crisp texture.

Final Thoughts

This Slow Cooker Broccoli Casserole with Cheddar and Fried Onions Recipe has become one of my go-to sides because it’s effortless, delicious, and crowd-pleasing every time. There’s something so comforting about the creamy cheese sauce paired with tender broccoli and that crunchy topping—it’s a combination I never tire of. I hope you’ll love making it as much as I do and enjoy sharing it with your family and friends. Give it a try, and let it bring a little cozy magic to your table!