Slow Cooker Green Bean Casserole with Cottage Cheese

Name: Slow Cooker Green Bean Casserole
Prep time: 15 min
Cook time: 200 min
Total time: 215 min
Ingredients: 2 pounds frozen green beans (thawed and thoroughly patted dry); 1 tablespoon olive oil; 8 ounces cremini mushrooms (finely sliced); 1 small white onion (finely diced); 3-4 cloves garlic (minced); ½ teaspoon dried thyme; ½ teaspoon fine sea salt; ¼ teaspoon freshly ground black pepper; 2 cups full-fat cottage cheese; ¾ cup whole milk; 1 cup shredded sharp cheddar cheese; ¼ cup finely grated Parmesan cheese; 1 tablespoon cornstarch; 1 tablespoon Dijon mustard; ½ teaspoon garlic powder; ½ teaspoon onion powder; ¼ teaspoon dried thyme; ¼ teaspoon freshly ground black pepper; 1 pinch ground nutmeg; ¼ teaspoon fine sea salt (or to taste); 1 tbsp butter; ¾ cup panko breadcrumbs; 2 tbsp finely grated Parmesan cheese; ¼ tsp garlic powder; 1 pinch salt; freshly ground black pepper

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This Slow Cooker Green Bean Casserole is creamy, cheesy, and so easy to make for the holidays. Made from scratch with green beans, mushrooms, and a creamy cottage cheese sauce, it’s finished with crispy Parmesan panko breadcrumbs.

A slow cooker filled with green bean casserole topped with crispy panko breadcrumbs.

I have a few tricks up my sleeve for staying cool-headed during Thanksgiving prep. One is pulling out the slow cooker so I can have a side dish cooking that I don’t have to babysit. Although I like to make things from scratch instead of relying on canned soup for my green bean casserole, I wanted something that felt just as easy.

This is where my magical creamy sauce comes in: I whip up cottage cheese, cheddar, Parm, and seasonings into a smooth, savory puree that takes barely a few minutes to prep. Coupled with a bag of frozen green beans (which are already prepped, hooray!), it’s topped with a golden breadcrumb topping.

I love making side dishes using my crockpot during the holidays because it frees up much-needed oven space. This one is especially great for Thanksgiving when I already have several other dishes going at once.

If you want an oven-baked version, try my green bean and mushroom casserole instead.

Recipe Overview

Skill Level

Beginner

Prep Time

15 mins

Cook Time

3 hrs 20 mins

A Few Key Ingredients

Below are the key ingredients you’ll need to make Slow Cooker Green Bean Casserole. You’ll find the full quantities in the recipe card further down the post.

ingredients for slow cooker green bean casserole.

Frozen green beans: I love using frozen green beans for casserole because they cut down the active prep time considerably. One thing to note, though, is that you have to thaw them and pat them really dry (otherwise things can get soggy fast!).

Cremini mushrooms: A classic inclusion in green bean casserole, the mushrooms add an earthy, savory flavor. Other good substitutes include portobello or button mushrooms. You can also omit them if you’re not a fan of mushrooms, though.

Cottage cheese sauce: I blend cottage cheese with Parmesan, cheddar, seasonings, and cornstarch to make a quick, creamy sauce that thickens as it cooks. I prefer full-fat cottage cheese here for the richer texture, but reduced-fat will also work.

Panko breadcrumbs: Are toasted with butter and a sprinkle of Parmesan to form a crispy, crunchy topping to sprinkle over the casserole. You can also use chunky, dry breadcrumbs if you don’t have panko to hand.

Common Mistakes to Avoid

Not draining the green beans well enough will make the casserole soggy. Make sure they have plenty of time to thaw and drain, then pat them as dry as possible.
Lifting the lid too often when using the slow cooker will cause it to lose a lot of heat, which will slow down the cooking process.
Overcooking the casserole will make the green beans lose their color and become very mushy. The frozen green beans have been blanched so are already halfway cooked before you even add them to the crockpot. Always check them at the lower end of the time range given for the heat you’re using so you can make sure they’re not overcooking.
Adding the panko topping too early will cause it to suck up moisture from the casserole, making it go soft. Hold off on sprinkling on the topping until you’re just about to serve (or even serve it in a separate bowl so guests can scatter it on themselves).

How to Make Slow Cooker Green Bean Casserole

Prepare the Green Beans

Thaw the frozen green beans completely. Drain them well and pat them very dry with paper towels or a clean kitchen towel.

Don’t rush this part. Extra water from the green beans can make the finished casserole too thin.

Cook the Mushrooms

Heat the olive oil in a large skillet over medium-high heat. Add the mushrooms and onion and cook for 6 to 8 minutes, stirring occasionally.

You want the mushrooms to release their liquid and for most of that moisture to cook off.

Add the garlic, thyme, salt, and pepper. Cook for another 30 to 60 seconds, just until fragrant.

process shot to cook the mushrooms, and whipping the cottage cheese mixture.

Make the Cottage Cheese Sauce

Add the cottage cheese, milk, cheddar, Parmesan, cornstarch, Dijon, garlic powder, onion powder, thyme, black pepper, nutmeg, and salt to a high-speed blender.

Blend for 1-2 minutes, until completely smooth and creamy with no visible cottage cheese curds remaining. The sauce will be rather thick.

Taste and adjust the seasoning. The sauce should taste slightly more intensely seasoned than you think it needs to be because the green beans will mellow the flavors.

assembling the green bean casserole into the slow cooker buy adding all the ingredients in.

Assemble

Lightly grease the inside of a slow cooker. Add the green beans and sautéed mushroom mixture. Pour the cottage cheese sauce over everything and gently toss until the beans are evenly coated.

Cover and cook on LOW for 4-5 hours or HIGH for 2-3 hours, until the green beans are tender and the sauce is hot and creamy. Avoid repeatedly opening the lid while it cooks.

Once done, gently stir the casserole. If the sauce seems slightly loose, leave the lid off for 10-15 minutes before serving. It will thicken further as it cools slightly.

Make the Crispy Panko

Make the topping shortly before serving. Melt the butter in a skillet over medium heat.

Add the panko and cook for 3-5 minutes, stirring frequently, until deeply golden and crisp. Remove from the heat and stir in the Parmesan, garlic powder, a small pinch of salt, and black pepper.

process shot to toast the breadcrumbs and adding it over the green bean casserole in the slow cooker.

Finish

Transfer the green bean casserole to a serving dish or leave it directly in the slow cooker. Scatter the toasted Parmesan panko generously over the top immediately before serving warm.

Recipe Notes

Lower carb: Swap the toasted panko topping for toasted, slivered almonds, which will add a nice crunch with fewer carbs. This is also a great gluten-free option.

Fresh green beans: Replace the frozen green beans with 2 lbs of fresh green beans, trimmed and halved. Blanch them in boiling salted water for 3 minutes, then immediately transfer them to a bowl of ice water. Drain and dry them thoroughly before adding them to the slow cooker.

Storage: Store cooled leftovers in an airtight container in the fridge for up to 3 days. Where possible, store the breadcrumb topping in a separate airtight container at room temperature. Freezing isn’t recommended.

Reheating: Reheat in the microwave until piping hot before sprinkling on reserved breadcrumbs.

The Most Important Tip: Keep the Water Out

If there’s one thing I would emphasize in this recipe, it’s moisture.

Frozen green beans and mushrooms both release water, and slow cookers retain moisture rather than letting it evaporate as an oven does. That’s why I recommend:

Thawing and thoroughly drying the green beans.
Cooking the mushrooms until most of their liquid has evaporated.
Keeping the lid on while the casserole cooks instead of repeatedly opening it.
Adding the panko topping at the end rather than cooking it in the slow cooker.

Those few steps will give you a much creamier casserole instead of a watery one.

Questions I Get Asked a Lot

Why is my casserole watery?

This is either because the beans weren’t thawed/patted dry thoroughly enough, or because the casserole hasn’t cooked for long enough. Keep in mind that it may seem a little loose once the cook time is up when you first lift the lid! It will thicken as it sits in the slow cooker for 10-15 minutes before serving.

Can I prep it ahead of time?

You can make the creamy sauce up to 3 days before you need it, stored in an airtight container in the fridge. You can also toast the panko 2-3 days before and, once cooled, store it in an airtight container at room temp.

Can I add fried onions?

Yes, you can either buy pre-fried crispy onions or fry them up yourself, then sprinkle on top of the casserole along with the panko.

What Can I Use Instead of Cottage Cheese?

Because cottage cheese makes up most of the creamy sauce in this particular recipe, I wouldn’t recommend swapping it without testing the recipe first.
If you don’t like the texture of cottage cheese, don’t worry. Blending it makes the sauce smooth and creamy, so you won’t have noticeable cottage cheese curds in the finished casserole.

Can I Use Canned Green Beans?

I prefer frozen or fresh green beans for this recipe because they hold their texture better.
If you use canned green beans, drain them very well and keep in mind that they’re already fully cooked, so they’ll become softer in the slow cooker.

Can I Use Fresh Green Beans?

Yes. Fresh green beans should work well here, but I would blanch them briefly first so they have a head start on cooking.
I wouldn’t add completely raw green beans without testing the timing because they may take longer to become tender than the rest of the casserole.

A crockpot filled with slow cooker green bean casserole and a serving spoon.

More Tips for the Best Green Bean Casserole

Don’t skip sautéing the mushrooms and onions. Adding them raw would introduce much more moisture into the slow cooker.
Use full-fat cottage cheese for a richer, creamier sauce. I would also shred the cheddar yourself when possible because it melts better than pre-shredded cheese.
And most importantly, add the crispy topping right before serving. Putting it on too early will cause the breadcrumbs to absorb moisture and soften.

More Thanksgiving Recipes

Thank you so much for being here and for cooking along with me. If you try this recipe, I’d love to hear how it turned out. Leave a comment and ⭐️ rating below.