Name: Slow Cooker Broccoli Casserole 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% recommended); 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’re on the hunt for an easy, comforting veggie side dish that comes out creamy, tender, and downright delicious every single time, then this Slow Cooker Broccoli Casserole Recipe is going to be your new best friend. I’ve made this casserole countless times for family dinners and potlucks, and honestly, it’s always a crowd-pleaser. The slow cooker does the heavy lifting, so you can set it and forget it while the magic happens. Keep reading—I’m going to share my favorite tips to make sure your casserole turns out perfect, every time.

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Why You’ll Love This Recipe

Effortless Cooking: The slow cooker does all the work, freeing you up to focus on other things.
Creamy Comfort: The combination of butter, flour, and milk creates a perfectly silky sauce that wraps the broccoli in flavor.
Crunchy Topping: Fried onions add that irresistible crunch that takes this casserole to another level.
Family Favorite: My family goes crazy for this dish, and I bet yours will too!

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

It might seem like a simple list, but these ingredients really play well together. Fresh broccoli is the star, and that rich cheddar combined with the creamy sauce makes this casserole feel indulgent without too much fuss.

Salted butter: Adds richness and helps create the roux that thickens the sauce.
All-purpose flour: The secret to a creamy, thick gravy that clings beautifully to the broccoli.
Milk (2% preferred): I like 2% milk for a balance of creaminess without being too heavy.
Salt: Enhances all the flavors.
Black pepper: Adds just a touch of warmth and spice.
Garlic powder: Delivers subtle depth without overpowering.
Fresh broccoli pieces: The star veggie—make sure the florets are bite-sized for even cooking.
Shredded cheddar cheese: Sharp or mild, cheddar melts perfectly and boosts that comfort food vibe.
Fried onions: The crispy topping that brings texture and flavor contrast to the creamy casserole.

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 best things about this Slow Cooker Broccoli Casserole Recipe is how adaptable it is. I love switching things up based on what we have handy or to keep things interesting. Feel free to get creative and make it your own.

Cheese swaps: I discovered this trick when I used sharp white cheddar instead of mild—it adds a nice tang that balances the creaminess.
Veggie combos: Mixing half the broccoli with cauliflower is a texture and flavor game-changer that my family loves.
Toppings: Fried onions are classic, but crushed Ritz crackers provide a buttery crunch if you want a different vibe.
Cream soups: For a shortcut, mixing in a canned cream of chicken or mushroom soup works well, but I prefer making the gravy from scratch for that fresh taste.

How to Make Slow Cooker Broccoli Casserole Recipe

Step 1: Make the Creamy Sauce Base

Start by melting your butter over medium heat in a small saucepan. Once it’s melted, whisk in the flour and let it cook for about 2-3 minutes. This is your roux—the thickening agent—so don’t skip this step! You’ll notice it forms into a smooth paste that’s the heart of your creamy sauce. Then, gradually whisk in the milk until everything is silky and lump-free. Season with salt, pepper, and garlic powder, and keep stirring gently until it thickens. This process takes a few minutes, but it’s the difference between a watery side and a luxurious, creamy dish.

Step 2: Combine Broccoli and Sauce in Slow Cooker

Next, spray your slow cooker basin with nonstick spray to prevent sticking. Pour in the fresh broccoli florets, then pour the creamy sauce right over the top. Give it a good stir to make sure every piece of broccoli is coated in that lovely gravy. This little stir helps everything cook evenly and makes sure the flavors meld beautifully as it cooks.

Step 3: Cook Low and Slow (or Quick and High)

Cover the slow cooker and choose your heat setting. For the best texture, I like HIGH for 1 hour or LOW for 2 hours. Midway through, give it a gentle stir—that way, you’ll help the broccoli cook evenly and catch any spots that may need extra attention. Then cover and cook for about 30 more minutes, or until the broccoli is tender but not mushy. Slow cookers all behave differently, so keep an eye the first time you make this to find your perfect timing.

Step 4: Melt in the Cheese and Top with Crunch

Once the broccoli is tender, sprinkle in the shredded cheddar cheese and stir it right in—your casserole will get that creamy, cheesy goodness we all crave. Then, sprinkle the fried onions on top. Cook uncovered for about 10 minutes more until the cheese is fully melted and the onions begin to crisp up slightly. That crunchy-on-top, creamy-below texture is what keeps me coming back to this recipe.

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Pro Tips for Making Slow Cooker Broccoli Casserole Recipe

Watch Your Slow Cooker: I learned the hard way that slow cookers vary widely—start checking tenderness 10 minutes before the suggested time.
Use Fresh Broccoli: Fresh florets give you the best texture; frozen broccoli is fine if thawed and drained to avoid watery casserole.
Don’t Skip the Roux: Making the butter-flour base really thickens the sauce—skip this and your casserole will be runny.
Add Crunch at the End: Put the fried onions on last and keep the lid off—they stay crispy instead of soggy.

How to Serve Slow Cooker Broccoli Casserole 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 usually keep it simple with extra fried onions on top, sometimes a sprinkle of freshly chopped parsley for color and a subtle fresh flavor. A little cracked black pepper over the serving just elevates the dish even more.

Side Dishes

This broccoli casserole pairs perfectly with roasted chicken or baked ham. I also love serving it alongside mashed potatoes or a simple rice pilaf for a complete weekend dinner my family adores.

Creative Ways to Present

For holidays or special dinners, I sometimes spoon this casserole into cute ramekins or small baking dishes for individual servings—guests love the personal touch, and it makes plating supper feel a bit fancier without extra effort.

Make Ahead and Storage

Storing Leftovers

I usually store leftovers in an airtight container in the refrigerator for up to 4 days. Just be sure it cools before you cover it to avoid condensation, which can make the topping soggy.

Freezing

I’ve frozen this casserole successfully, but I recommend freezing it before adding the fried onions or cheese topping. When ready to eat, thaw overnight in the fridge and then bake to reheat and add crunchy topping fresh.

Reheating

To reheat, I pop leftovers in the oven at 350°F for about 15-20 minutes until warmed through. This keeps the texture great—microwaving can sometimes make it soggy, so oven reheating is my go-to.

FAQs

Can I use frozen broccoli for this Slow Cooker Broccoli Casserole Recipe?

Yes, you can! Just be sure to thaw the broccoli completely and drain off any excess water before using. This prevents the casserole from becoming watery and helps maintain the creamy texture you want.
How do I prevent the casserole from drying out in the slow cooker?

Keeping the slow cooker covered during most of the cooking time helps trap moisture. Also, follow the recipe’s timing closely, and stir the casserole halfway through cooking to distribute heat evenly.
Can I make this Slow Cooker Broccoli Casserole Recipe vegan or dairy-free?

Absolutely! Use dairy-free butter and milk alternatives like almond or oat milk, and swap cheddar for a plant-based cheese that melts well. For the crunchy topping, look for vegan fried onion substitutes or use breadcrumbs.
Is it necessary to make the roux with butter and flour?

While it’s the traditional way to get a creamy sauce, you can thicken the casserole with cornstarch mixed with cold milk as an alternative. I recommend the roux though because it creates a smooth, rich sauce that’s hard to beat.

Final Thoughts

I absolutely love how this Slow Cooker Broccoli Casserole Recipe comes together with minimal effort but maximum comfort. Whether you’re a busy parent, a beginner cook, or just looking for a reliable veggie side everyone will adore, this is the recipe I always come back to. Give it a try—you’ll find that the creamy sauce, tender broccoli, and crunchy topping combo is simply irresistible. Trust me, this casserole is one you’ll want on repeat for weeknight dinners and holiday spreads alike.