Crockpot Green Bean Casserole
How to make Crockpot Green Bean Casserole from scratch. Fresh green beans and an easy homemade creamy filling make this recipe the best!
Prep: 20 minutes
Cook: 5 hours 30 minutes
Total: 5 hours 50 minutes
Servings: 10 servings
Ingredients
FOR THE CASSEROLE:
- 2 pounds fresh green beans
- 2 tablespoons unsalted butter
- 1 medium yellow onion thinly sliced
- 16 ounces baby bella mushrooms thinly sliced
- 3 tablespoons all-purpose flour
- 2 cups whole milk a lower fat milk may curdle, so swap at your own risk; for more decadence, use part half-and-half
- 1 teaspoon kosher salt
- ½ teaspoon ground black pepper
- ⅛ teaspoon ground nutmeg
- 1 tablespoon sherry vinegar
- 1 cup shredded cheddar cheese or gruyere cheese*
FOR THE TOPPING:
- 1 ½ cups fried onions store bought or homemade; to make your own, see blog post above; about 3 ounces
Instructions
- Trim the green beans and cut into 1-inch pieces (don’t be tempted to cut them larger than this, or your green beans will turn out too firm). Add them to a 5 or 6-quart slow cooker.
- Melt the butter in a wide saucepan over medium heat. Add onion and mushrooms. Cook, stirring occasionally, until the onion is soft and golden and the mushrooms brown and have given up their liquid, about 12 minutes.
- Sprinkle the flour over the top. Cook, stirring constantly, for 1 to 2 minutes more, until all of the flour turns golden and no white bits remain. The vegetables will seem dry.
- Slowly add the milk a few splashes at a time, stirring between each addition to prevent lumps from forming. Increase the heat to medium high. Stir in the salt, pepper, and nutmeg. Cook and stir, allowing the sauce to bubble gently, running a wooden spoon or rubber spatula along the bottom of the pan. Continue cooking and stirring for 6 minutes, then stir in the sherry vinegar. Cook 2 to 4 more minutes, until the sauce has thickened to resemble a creamy gravy. It should be clearly thicker than it was when you started, but still be loose enough to easily coat the green beans.
- Pour the sauce over the green beans.
- Stir to combine. Cook on LOW for 3 to 5 hours, until the green beans are pleasantly tender but still have a bit of crispness (i.e. are done but not mushy). The amount of cook time you need will vary based on your slow cooker and your preference for how al dente you like the green beans. I recommend checking at the 3-hour mark to gauge their progress. We like our green beans pretty crisp, so I only let ours cook a little beyond 3 hours. If at 3 hours you'd like your green beans more done, give the casserole a stir, recover, and keep cooking until they reach your desired texture.
- Five minutes prior to serving, stir in the cheese. Recover, turn to WARM, and let cook 5 minutes to melt the cheese.
- Immediately before serving, if desired, transfer the green beans and sauce to a serving dish. Sprinkle the fried onions over the top (if you will be serving right out of the slow cooker, remove the lid, then sprinkle the onions on top of the green beans in the slow cooker). Enjoy hot!
Notes
- *I love either gruyere or cheddar here; gruyere is more intense and nutty and tastes classic with the nutmeg; cheddar is more “all-American”, so choose whichever one you and your family prefer.
- TO MAKE AHEAD: Prepare the mushroom sauce up to 1 day in advance, and place it in an airtight storage container in the refrigerator. Trim and cut the green beans up to 2 days in advance, and store them in a separate container in the refrigerator.
- You can also add the trimmed and cut green beans to a slow cooker, and stir them together with the mushroom sauce. Cover and refrigerate the slow cooker for up to 1 day, then finish the recipe as directed.
- TO STORE: Refrigerate the casserole in an airtight storage container for up to 4 days.
- TO REHEAT: Rewarm leftovers in a baking dish in the oven at 350°F.
- TO FREEZE: Freeze green bean casserole in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating. The crispy onions will become soggy, but the casserole will still taste delicious.
Nutrition
Serving: 1(of 10)Calories: 199kcalCarbohydrates: 17gProtein: 8gFat: 12gSaturated Fat: 7gCholesterol: 23mgPotassium: 486mgFiber: 3gSugar: 7gVitamin A: 888IUVitamin C: 12mgCalcium: 181mgIron: 1mg
