Slow Cooker Broccoli Casserole Recipe

If you dream of a superstar side that’s easy enough for weeknights and delicious enough for holiday tables, this Slow Cooker Broccoli Casserole will absolutely win your heart. Creamy from a quick homemade sauce, bursting with tender broccoli, layered with cheddar, and topped with those irresistible crispy fried onions, it’s a cozy classic reimagined to fit right into your slow cooker. No need to fuss with the oven or worry about the timing—just set it and let the rich flavors meld beautifully while you get on with life. This casserole is pure comfort and crowd-pleaser all in one gorgeous, bubbling dish.

Ingredients You’ll Need

This Slow Cooker Broccoli Casserole relies on simple, familiar ingredients that each bring something special to the table. Don’t skimp—every element from the butter to the fried onions plays a role in making the dish savory, creamy, and impossible to resist.

• Salted Butter: Adds richness and a hint of salt, forming the base for a luscious sauce.
• All Purpose Flour: Helps thicken the sauce, ensuring it hugs every bite of broccoli.
• Milk: Makes the sauce creamy and smooth—whole milk will be extra luxurious, but 2% works too.
• Salt: Essential for seasoning and enhancing all the flavors.
• Black Pepper: Adds just the right amount of warmth and bite without overpowering.
• Garlic Powder: Infuses the casserole with savory depth in just seconds.
• Fresh Broccoli Pieces: The star of the show! Opt for bite-sized florets so they cook up perfectly tender.
• Shredded Cheddar: Melts into the broccoli, adding cheesy comfort and that wonderful orange hue.
• Fried Onions: The magical crunchy topping you’ll want on every bite—don’t skip this finishing touch!

How to Make Slow Cooker Broccoli Casserole

Step 1: Prep the Broccoli

Start by washing and cutting your fresh broccoli into small, uniform pieces. This ensures they’ll all cook evenly in the slow cooker. If you notice any thick stalks, give them a quick peel and slice so they turn wonderfully tender, just like the florets.

Step 2: Make a Simple Cheese Sauce

In a saucepan over medium heat, melt the salted butter and sprinkle in the flour. Whisk continuously to create a smooth, bubbly roux—this takes about one minute. Next, gradually pour in the milk, whisking constantly until the sauce thickens and is completely smooth. Stir in salt, black pepper, and garlic powder for a seasoning boost, then remove from heat and add a cup of the shredded cheddar. Stir until the cheese melts into the sauce and everything is beautifully creamy.

Step 3: Combine Everything in the Slow Cooker

Put the broccoli pieces right into your slow cooker. Pour the cheesy sauce over top, then use a big spoon or spatula to toss everything together. Make sure the sauce coats all the broccoli for the best flavor in every spoonful. Sprinkle the remaining cheddar over top—it’ll melt into gooey perfection while cooking.

Step 4: Cook Low and Slow

Cover and cook the Slow Cooker Broccoli Casserole on low for around 2½ to 3 hours. You’ll know it’s ready when the broccoli is fork-tender and the cheese is bubbling around the edges. Avoid peeking too much to keep in all that helpful steam!

Step 5: Top and Finish

About 10 minutes before serving, sprinkle the fried onions over the casserole in a generous, even layer. Pop the lid back on just to warm everything through—the onions will stay crunchy while infusing the top with their savory flavor. Serve straight from the slow cooker for ultimate ease.

How to Serve Slow Cooker Broccoli Casserole

Garnishes

A sprinkle of extra shredded cheddar or a little chopped parsley on top can make this casserole look even more inviting. A pinch of cracked black pepper or a tiny sprinkle of smoked paprika brings a pop of color and a fresh finish right before serving.

Side Dishes

Slow Cooker Broccoli Casserole pairs beautifully with roast chicken, turkey, ham, or even grilled steak. For a vegetarian spread, serve it alongside rice pilaf, garlic mashed potatoes, or a crisp green salad to brighten the meal.

Creative Ways to Present

Spoon individual servings into small ramekins for a fun, personal touch at dinner parties, or serve from a vintage casserole dish for family-style charm. If you’re prepping dishes ahead for a potluck, just bring your slow cooker insert straight to the table—rustic and practical!

Make Ahead and Storage

Storing Leftovers

Let any remaining Slow Cooker Broccoli Casserole cool to room temperature. Pop it in an airtight container and refrigerate for up to three days. The flavors deepen as it sits, so leftovers are extra delicious!

Freezing

If you want to freeze, portion the casserole into freezer-safe containers, skip the fried onion topping for now, and freeze for up to a month. Thaw overnight in the refrigerator before reheating, then add fresh fried onions for crunch right before serving.

Reheating

Warm leftovers in the microwave or in a 300-degree oven until hot and bubbly. If you notice the sauce has thickened up in the fridge, add a splash of milk to bring back the creamy texture. Top with more fried onions to refresh that crispy finish.

FAQs

Can I use frozen broccoli instead of fresh?

Yes! If you’re using frozen broccoli, there’s no need to thaw—just toss it in as is. The only difference may be a touch more liquid, but the end result tastes great.

What can I substitute for cheddar cheese?

Any melty cheese works well here—try Monterey Jack, Gouda, or a mild Swiss for a twist on the usual flavor. Mixing in some mozzarella makes the casserole extra gooey!

How can I make this gluten free?

Simply swap the all-purpose flour for a gluten-free blend or use cornstarch to thicken the sauce. Just be sure your fried onions are gluten-free, too, since some store-bought brands add flour to the coating.

Can I double the recipe for a crowd?

Absolutely! Just be sure your slow cooker is large enough—at least six quarts for a double batch. The cooking time may be a bit longer, so check the broccoli for tenderness before serving.

Is this casserole suitable for meal prep?

Slow Cooker Broccoli Casserole is fantastic for meal prep. You can assemble it in the slow cooker the night before (hold off on the onions) and refrigerate until ready to cook the next day—perfect for busy weeks or make-ahead holiday meals.

Final Thoughts

There’s nothing quite like the cozy comfort of Slow Cooker Broccoli Casserole. Whether it’s the centerpiece of a family dinner or a simple way to sneak veggies onto your holiday table, this dish makes everyone feel right at home. Give it a try—you’ll find yourself coming back to this creamy, cheesy favorite again and again!

Print