Slow Cooker Broccoli Casserole

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This Slow Cooker Broccoli Casserole is made from scratch (no canned soup) and is the perfect side dish for holiday dinners but easy enough to make any weeknight. It’s cheesy and creamy with the perfect crunch from fried onions and made simple in the crockpot!

cheesy broccoli casserole on a white plate.

Crockpot Broccoli Casserole

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Sometimes we all need a big helping of some creamy, cheesy, and wholesome comfort food. That’s why I know you’re going to love this classic cheesy broccoli casserole. It’s a simple, delicious, and effortless way to get everyone to eat their veggies and I’m not just talking about the kids!

I’m sure I don’t have to tell you how much I adore using a slow cooker. It makes everything from appetizers like crockpot spinach artichoke dip, to entire meals like this chicken potatoes and green beans recipe, and dessert like this chocolate lava cake.

It’s a game changer for many busy families and it’s dishes like this broccoli cheese casserole that remind us why timeless recipes never go out of style.

Sure it’s creamy and cheesy, but it’s loaded with broccoli too! Go back for seconds…or thirds…and feel good about eating your veggies 🙂

If you want more broccoli cheddar flavors, try my crockpot broccoli cheddar soup.

Why you’ll love this Broccoli Casserole recipe

Slow Cooker Recipe – Aside from the main dish, I love making side dishes in the crockpot. Bonus is you can serve right out of it when set on WARM.

Traditional Broccoli Casserole – There’s no need to mess with perfection. This tried and true recipe made from scratch uses no canned soups but instead gets its thickness from a roux and richness from the milk and cheese.

Taste and texture – It has so much flavor! The broccoli is nice and tender but still has a bite to it because it’s perfectly cooked every time. Never mushy.

Side dish for any occasion – Serve it during the holidays for Thanksgiving dinner or Christmas or enjoy it during a busy weekday or on a lazy Sunday!

Budget-friendly – There are just a few simple ingredients that go into making it, and most of them you probably already have in your kitchen.

cheesy broccoli casserole in a white serving dish.

Equipment you’ll need

6-Quart Slow Cooker – This is the size I use and it makes enough of this casserole to serve 8 people.
Kitchen knife – For chopping a head of broccoli quickly and easily.
Small saucepan – Just something small is all you need to make a quick roux.
Whisk – The best way to blend a sauce into a smooth consistency.
Cheese grater – I always recommend grating your own cheese off the block.

Ingredients

Below is a list of the ingredients you’ll need to gather to make this recipe. Scroll all the way down for the full recipe card.

SALTED BUTTER – I use salted butter because I like that extra bit of flavor, however, if unsalted is what you have, go ahead and use it. We will be adding extra salt as well and you can play around with the amount if needed.
ALL-PURPOSE FLOUR – Combined with the heated butter to create a paste, otherwise known as a roux. This will help thicken the sauce.
MILK – Used to turn the roux into a creamy sauce. Use whatever milk you have on hand. The higher the fat content in your milk, the richer your sauce will be.
SALT, GARLIC POWDER, & PEPPER – Season the sauce and adjust the amount of salt to taste. You may find you don’t need any if you’ve used salted butter.
FRESH BROCCOLI FLORETS – Wash and cut your head of broccoli into florets. You can also add in chopped pieces of the stem if you’d like, or freeze it to make stock later on. If you want to save a bit of time, you can buy broccoli pieces pre-cut from your local grocery store (this is what I usually do).
CHEDDAR CHEESE – Freshly grated cheddar melts so nicely and adds incredible flavor. Avoid the pre-shredded packaged cheese it’s just not the same.
FRIED ONIONS – Such a yummy way to add a crunchy topping to any casserole! The flavor of the onions also pairs nicely with the taste of the broccoli. If you don’t like onions, cracker crumbs or bread crumbs can be used.

overhead shot of labeled ingredients laid out to make broccoli casserole.

How to make Slow Cooker Broccoli Casserole

STEP ONE: Melt butter in a small saucepan over medium heat and whisk in the flour for 2-3 minutes until it becomes a light brown paste with a nutty aroma. Then, slowly whisk in the milk until the roux has dissolved and the sauce is smooth, stirring continuously. Season with salt, pepper, and garlic powder.
STEP TWO: Spray the basin of a 6-quart slow cooker with cooking spray. Toss in the chopped broccoli then pour the sauce mixture overtop. Stir to combine.
STEP THREE: Cover with the lid and cook on high for 1 hour or low for 2 hours. Stir it and replace the lid and cook for another 30 minutes until the broccoli is tender.
STEP FOUR: Sprinkle with cheese, stir and then top with fried onions. Continue cooking uncovered for another 10 minutes until the cheese has melted. Enjoy!

collage of 4 photos showing the process of making broccoli casserole in a slow cooker.

What to serve with Slow Cooker Broccoli Casserole

This slow cooker version is a dish that can replace your regular veggie side dish with so many mains, like chicken breasts.

For something a little different during the holidays, it’s a perfect pairing with slow cooker turkey breast or Cornish game hens in the crockpot.

The next day use up all the leftovers and make these turkey and stuffing egg rolls and leftover broccoli casserole!

It also works as a great vegetarian main for meatless Mondays or non-meat-eating families. Serve it overtop some brown rice for a complete meal.

During the week or for a casual weekend dinner, I like to have it with meatloaf muffins, easy garlic steak bites, or slow cooker chicken thighs with potatoes and carrots.

So simple and so good!

Tips & Suggestions 🥦🧀

Shredded mild cheddar was used but try adding Parmesan as well. For variation, try sharp cheddar cheese, white cheddar, or an aged cheddar that will add a nice sharpness to balance out the creaminess of this dish.
Fried onions are used for crunch and flavor but crushed Ritz crackers can also be used.
You can use frozen broccoli but thaw it first. Drain any excess water.
Replace half the broccoli with cauliflower for a neat combination of the two.
If you would like to use a canned cream soup, I suggest making my homemade cream of chicken substitute! You can also use cream of celery soup, cream of mushroom soup, and of course, cream of broccoli for a different flavor profile.
Each slow cooker varies so cooking time may need to be adjusted. Keep an eye on yours so it doesn’t burn.

How to reheat and store Slow Cooker Broccoli Casserole

How to store leftovers

Store leftovers in an airtight container in the fridge. If you’re making 2 casseroles to save one for later, I suggest freezing right from the jump.

How long with Cheesy Broccoli Casserole last in the fridge?

When stored properly, it will last in the fridge for up to 4 days. The onions will get soggy over time, so feel free to top it with a few more once you reheat it.

Can I freeze Broccoli Casserole?

Absolutely! That’s one of my favorite things about a casserole. If I’m making more than I need, I will portion some out into an aluminum foil dish and wrap it tightly with saran wrap. It stays frozen for up to 4 months, so it makes a great quick and easy dinner idea or a freezer meal for a friend or neighbor.

How to reheat Crockpot Broccoli Casserole?

If you’re reheating a large portion, pop it back in the slow cooker to heat through. You can also reheat it on the stovetop or in the oven using a casserole dish. The microwave is handy for a single serving or two.

overhead shot of a wooden spoon in crockpot broccoli casserole.

FAQs

How long can I keep it on the warm function?

Once it is cooked, I’d suggest eating it right away if you can. Otherwise, no more than 2 hours. After that, allow it to cool and transfer it to the fridge.

Should you blanch broccoli before putting it into the casserole?

Blanching can be a useful process sometimes, but this is not one of them. Normally you blanch your veggies to bring out their bright green color, partially cook them to ensure they cook properly, and prevent sogginess.

There is no need for that because the slow cooker cooks them perfectly, and it’s covered in the cream sauce anyway, so we’re not too concerned about color!

How long does broccoli take in the slow cooker?

Each slow cooker cooks differently, so keep an eye on it after about 1 hour. There’s nothing wrong with taste testing along the way. At minimum, it will take about 1 hour on high, but again, don’t stray too far away!