Slow-Cooker Green Bean Casserole

A slow-cooker green bean casserole takes advantage of the kitchen's real estate by freeing up the oven and still producing a creamy, deeply comforting dish. This slow-cooker green bean casserole is a great addition to holiday menus, but it's easy enough to make for a weeknight side dish.

A Crockpot green bean casserole is a bit different from your standard casserole. In place of cans of mushroom soup, we use jarred Alfredo sauce for the same decadent mouthfeel but with a more elevated flavor. Water chestnuts and mushrooms provide a yin-yang of textures: toothsome, a bit crunchy, and a nice contrast to the creamy sauce. You'll still find the classic casserole toppers—French fried onions—because they're quite simply a requirement. But to up the crunch factor (and, of course, make this dish more Southern), we've added some chopped pecans.

Learn how to make this slow-cooker green bean casserole, and if you try it, be sure to leave us a recipe review so we'll know how well you enjoyed it.

The Slow Cooker Is the Perfect Way To Make This Creamy Casserole

Green bean casseroles fill a special place in the holiday meal plan assortment. It's both a vegetable side dish (necessary to balance out all those cakes and pies) and a rich, cheesy casserole (thanks to creamy sauces and loads of cheese). Not only does this slow-cooker green bean casserole check all the boxes for the standard dish—creamy, comforting, and fresh—but also it's made in a slow cooker or Crockpot, saving your oven for other tasks.

The low and slow heat is the perfect way to cook green beans. It warms them gently until tender but doesn't overcook them and leave them mushy or stringy. And because the beans are cooking in the rich cream sauce, they absorb just enough flavor to taste extra rich and creamy, not watered out and bland.

Ingredients for Slow-Cooker Green Bean Casserole

A classic casserole like thi sone requires just a handful of easily accessible ingredients.

• Green beans: This Crockpot green bean casserole calls for frozen green beans. They hold their texture and snap better than canned green beans. You do not need to thaw them before making the dish.
• Alfredo sauce: Instead of cream of mushroom soup, we're calling on jarred Alfredo sauce for the creamy factor you know and expect in a green bean casserole. Alfredo sauce is typically made with Parmesan cheese, milk, butter, and salt and pepper, which keeps the flavors in this casserole simple and satisfying. You'll add more Parm later to amp up that cheesy flavor.
• Mushrooms: If you like the umami that cream of mushroom soup provides most green bean casseroles, you'll be glad to see mushrooms in this slow-cooker version, too. We call for jarred mushrooms in this recipe, but fresh mushrooms will still turn tender and delicate and add a hint of earthiness to the final dish's flavor.
• Water chestnuts: This ingredient is optional, but once you try it, you'll understand why it's common in most traditional green bean casseroles. Water chestnuts, as the name might imply, are aquatic vegetables that are a bit sweet and nutty. But they're really valued for their crunch factor.
• French fried onions: No green bean casserole is complete without French fried onions, and we surely didn't skip them in our recipe. In fact, we doubled up the amount and put some in the green bean mixture while is cooks and some on top for both a beautiful presentation and a nice crispness.
• Parmesan cheese: Echoing the flavors of the Alfredo sauce, this recipe calls for Parmesan cheese. If you can, splurge for the block and grate your own. Bagged Parm is often coated in an anti-caking powder that keeps it from melting beautifully.
• Pecans: For additional crunch (and a Southern touch), we're adding pecans to this green bean casserole. They'll get toasted at the end with the second half of French fried onions so they're fragrant and flavorful just before serving.

How To Make Slow-Cooker Green Bean Casserole

This recipe is made in a four-quart slow cooker. You could double it and make it in a larger eight-quarter Crockpot if you have one:

• Step 1: Combine ingredients: Spray the slow cooker's insert with cooking spray. Then, in a large bowl, combine the frozen green beans, Alfredo sauce, diced water chestnuts, mushrooms, Parmesan cheese, pepper, and half of the French fried onions. Spoon the green bean mixture into the greased slow-cooker insert.
• Step 2: Cook on low: Set a timer for 4 hours and 30 minutes, and cook the green bean mixture on low. Resist the urge to remove the lid while the casserole cooks. Every time you do, it takes the appliance a significant amount of time to get back up to cooking temperature. Look through the lid, and after 4 hours, start checking for signs of bubbles. Once the casserole is bubbling, it's nearly finished.
• Step 3: Toast the toppings: Add pecans and remaining French fried onions to a medium skillet, and heat slowly over medium-low heat. Stir every few seconds, and cook for 1 to 2 minutes or until the pecans and French fried onions are toasted. They will also start to release odors and become fragrant as they heat and toast.
• Step 4: Top the casserole: Once the toppings are fully toasted, you can sprinkle them on the green beans. Or, if you're preparing to serve the casserole, spoon the beans into a serving dish, and then sprinkle on the French fried onions and pecans.

How Long Does Slow-Cooker Green Bean Casserole Cook?

If you're cooking on low, plan for 4 1/2 hours cook time. You can bump the temp up to high for an hour to shave off some of the cook time, but watch for signs of burning, and turn it back to low after an hour.

If you like the look of this green bean casserole but need it cooked faster, try this Old-School School Green Bean Casserole.

Can You Make Green Bean Casserole Early and Reheat It?

Absolutely, you can cook a green bean casserole two to three days before you plan to serve it. Then, heat it slowly in the oven to get it ready to serve. Save the final layer of pecans and French fried onions until it's nearly time to eat.

Alternatively, you can mix together all the ingredients for this green bean casserole, and store them in an airtight container or the slow cooker crock (covered with plastic wrap) up to 2 days in the fridge. Then, when you're ready to cook the casserole, put all of the green beans in the slow-cooker crock, and cook it.

More Vegetable Side Dishes

Check out these favorites that complement any dish:

• Air Fryer Asparagus
• Crispy Potato Galette
• Broccoli Cheese Casserole
• Roasted Broccoli
• Tennessee Onions

Editorial contributions by Kimberly Holland.