Slow Cooker Green Bean Casserole Recipe

Slow Cooker Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!

As much as I may identify as a "foodie" or a "lover of food," there is one thing I emphatically am not. I am not a food snob.

So when someone makes the Campbell's original green bean casserole recipe with canned green beans, canned cream of mushroom soup, and canned fried onions, I'm all over it.

And yet, the foodie in me has been wondering for quite some time... is there a better way?

Crock Pot Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!

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Of course there is a better way! In this age of the Food Revolution, there is definitely a better way to Green Bean Casserole.

Now I know that sounds bold. It's quite an assertion to say that MY recipe is better than the version that has been beloved for 60+ years. That Campbell's recipe is practically an institution, gracing Thanksgiving tables year after year, all across the country.

But mine is made in a crock pot. On the day you use your oven the most, make this casserole in a crock pot.

But it gets better! It gets even better.

The Green Beans

Let me just get this out of the way: I am NOT recommending fresh beans here. I wish I could... I would love to... I think they would be The Ultimate.

But, here's the thing. I called my sister.

Monica is in charge of the Green Bean Casserole every Thanksgiving. If she is not willing to trim, chop, and blanch fresh green beans, then I'm not either. It just won't work. If Monica's not going to even consider my recipe, I'm not going to make it.

But canned green beans? In a crock pot? Sounds like a crock of mush.

So where does that leave us? We are left with frozen green beans. (Note: I have instructions for substituting fresh in the recipe notes for all your over-achievers out there).

And you know what? I really like the frozen green beans. You cook them in the microwave before you stir them into the sauce, and they taste great. They held their shape rather than turning to mush. And most importantly: They are convenient.

Crock Pot Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!

The Mushroom Sauce

We are ditching the canned cream of mushroom soup and making our own from scratch. The reason you are okay with this is because you can make it the night before.

It's also incredibly easy. Mushrooms sautéed in butter and garlic. Stir in some flour. Stir in chicken broth and cream. Simmer. Done.

Crock Pot Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!

The French Fried Onions

There are some traditions you just don't mess with, and the canned fried onions on green bean casserole is one of them.

With an oven-baked Green Bean Casserole, you assemble everything together and bake it. With a slow cooker, these crispy onions become a potential hazard. If you add them right away, they become softened and chewy. Not appetizing.

So, I add the crispy fried onions right at the end, right before serving. It's an easy solution with no down-side.

Crock Pot Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!

Green Bean Casserole For a Crowd

Reader Liz wants to make Green Bean Casserole for about 30 people, so I tripled the recipe (roughly) and tested it out. Great news! 3x-ing the recipe is a GO. See the recipe notes below for exactly what to do. At this capacity, you'll easily be able to feed 30 - 40 people as part of your general Thanksgiving feast.

WARNING: You need a large stock pot or Dutch Oven (at least 5.5 quarts) AND a large slow cooker (at least 6.5 quarts). I use this crock pot and it was filled RIGHT to the brim as you can see in the photo above.

I did not increase the amount of French Fried canned onions simply because the crock pot only has so much surface area. If you are going to serve the Green Bean Casserole on a buffet table, you may want to replenish the canned onions as the casserole is depleted. Or, transfer portions of the casserole to serving bowls and top those with the French Fried onions.

Be sure to read the recipe notes (at the end of the recipe) for my make-ahead instructions. Or if you want to use fresh green beans.

5 from 7 votes

Slow Cooker Green Bean Casserole Recipe

Slow Cooker Green Bean Casserole is a delicious combination of from-scratch cooking and slow cooker convenience. You'll want this on your menu all year round!
Course Side Dish
Cuisine American
Keyword green beans, slow cooker
Prep Time 5 minutes
Cook Time 2 hours 20 minutes
Total Time 2 hours 25 minutes
Servings 10 servings
Calories 312kcal
  • 3 tablespoons butter
  • 1 pound white button mushrooms wiped clean, sliced or broken into pieces
  • 3 cloves garlic minced
  • salt and freshly ground black pepper
  • 3 tablespoons all-purpose flour
  • 1 1/2 cups low-sodium chicken broth
  • 1 1/2 cups heavy cream
  • 2 (12 ounce) packages frozen cut green beans (see notes)
  • 3 cups canned fried onions
  • n a large, deep skillet, saucepan, or Dutch oven, melt the butter over medium-high heat until foaming subsides. Add mushrooms, garlic, 3/4 teaspoon salt, and 1/8 teaspoon pepper.
  • Cook until the mushrooms have released most of their liquid, about 5 minutes. Stir in flour and cook for one minute. Whisk in broth, scraping up any brown bits from the bottom of the pan. Bring to a boil, whisking constantly.
  • Reduce heat to medium. Whisk in cream and simmer until the sauce has thickened, about 5 minutes. Season to taste with salt and pepper.
  • Meanwhile, cook the beans in the microwave according to the package instructions (or microwave on HIGH power for 4 to 5 minutes; let stand 1 minute before removing from the microwave). Transfer to a colander or salad spinner and drain well. If using a salad spinner, spin out any liquid and drain.
  • Add the green beans to the pot with the mushroom sauce and toss until evenly coated. Transfer the beans and sauce to a crock pot.
  • Cook on HIGH for 2 hours or LOW for 4 hours or until a thermometer inserted in to the middle of the casserole reaches 165 degrees. Top with canned fried onions immediately before serving.

Recipe Notes

  • For the most part, I found frozen green beans in 12-ounce packages. If you find 10-ounce packages, I would still stick to 2 packages. I have tried the recipe with 3 (10 ounce) packages and there was not enough sauce for that many beans.
  • Be sure to use frozen cut green beans, not “French” green beans (the long, stringy ones) or whole, uncut beans (you’d just have extra work cutting them).
  • To substitute fresh beans, start by trimming them and cutting them in half. Then, bring 4 quarts water and 1 Tablespoon salt to a boil. Meanwhile, fill a large bowl with ice and water. Cook the beans about 5 minutes, until bright green and crisp-tender. Drain the beans and immediately plunge into the ice water. Drain well before adding them to the sauce in Step 5.
  • To triple the recipe for 30 to 40 people, increase the ingredients as follows: 1/2 cup (1 stick) butter 3 pounds white button mushrooms, wiped clean and sliced or broken into pieces 1 bulb garlic (9 to 10 cloves) 3 teaspoons salt and 1/2 teaspoon pepper 1 cup flour 4 1/2 cups chicken broth 4 1/2 cups heavy cream 6 (12 ounce) packages of frozen cut green beans 3 cups canned fried onions (or more if desired)
  • 3x recipe instruction changes: Cook the mushrooms for about 10 minutes in Step 2 and simmer the sauce for 10 minutes in Step 3. Cook on HIGH for 2 hours or LOW for 4 hours (or until a thermometer reaches at least 165 degrees in the middle of the casserole). Add more canned onions throughout serving time if the top layer is depleted, if desired.
  • The mushroom sauce may be prepared in advance, cooled, and refrigerated overnight. Increase the crock pot time to 3 hours on HIGH or 5 hours on LOW.
  • If using fresh beans, they may be blanched the night before, cooled, and stirred into the cooled mushroom sauce and refrigerated overnight. Increase the crock pot time to 3 hours on HIGH or 5 hours on LOW.
  • Adapted from Cook’s Illustrated Magazine, November & December 2006 issue.


Calories: 312kcal


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  1. Joey

    Just made over the holidays for a family dinner…..I love using the crockpot (and liners) to help with clean up at the end and to not have too many things going on around meal time. Everyone, including the little ones, was a fan and it was gone by the end of the night. I mixed in some of the fried onions into the green beans ahead of time and let them all cook and get comfy together. PERFECT. 5 stars

  2. Ellen

    Can you double this recipe? I think the tripled version is going to be too much, but since it requires some changes to the recipe, I’m curious if that goes for doubling too. I’ve only ever made the single version and love it!!!

    1. meggan

      Hi Ellen – YES! I’ve doubled it and it still fit in my crockpot. And it was amazing. Feel free to mix in more of the fried onions too – that’s what I did. :D Happy Thanksgiving! -Meggan

  3. Chris Everette

    So I came across this recipe because I was looking at making cream of mushroom from scratch. You have a recipe for condensed cream of mushroom that is slightly different than this recipe calls for. It seems the condensed soup you made has a bit more depth to it. Would I just add water to that one and substitute it for what is in this one? What are you recommendations? Thanks in advance.5 stars

    1. meggan

      Hi Chris! Yes, this recipe is basically the cream of soup in the un-condensed version. I think (but maybe I’m wrong) that if you make traditional green bean casserole, you would add some sort of liquid to it to thin out the canned cream of soup. So my recipe basically factors that in. But in the event that I’m wrong, or you just want to use the condensed version, I would make the sauce with the condensed soup and just see what you think. Make it, taste it, throw it all together, if it seems too thick you could add water, chicken stock, milk, whatever you want. Does that make sense? I’d make it and go with your gut, literally and figuratively. I hope this helps. If you have other questions just let me know! -Meggan

  4. Lee

    I would like to cut back on the milk added, as I cannot tolerate it very well. Could I add whole milk and broth? I think I would need to add more flour to make sure it thickens enough, do you think?

    1. Lee

      Hi Meggan,
      Thanks for the response. I would be afraid the coconut would taste weird, but I did think about using maybe plain Greek yogurt instead. What do you think?

    2. meggan

      Hi Lee, I once had a casserole with the coconut cream and you never would have known it was coconut cream. So that’s the only reason I suggested it… but I completely understand your fears. I am not sure how Greek Yogurt would work. It might work perfectly, but I just have no idea! I haven’t used it as a thickener before. If you think you can tolerate the whole milk, that is within the realm of my experience. I would just go with equal parts fat (butter) and flour, you can always add more milk if it’s too thick. And if it’s too thin, you mash up more butter and flour in your hand (cold) and toss it in to the hot sauce and whisk it.

    3. meggan

      Hi Lee, I do think you could probably substitute whole milk and use more flour (how much, I’d have to test to see). However, my gut reaction is to suggest a milk substitute such as coconut cream. The thick one. I can test it that way in the next day or so. Do you have a preference? Just let me know!

  5. Well thank you for figuring out a way to skip the canned soup on this recipe. We make this every year but I never really like using the canned soup either . . . but it’s Thanksgiving so we keep making it anyway . . . so thanks for the breakthrough! I made your Chipotle copycat guacamole at lunch today, and I made the salsa the other night . . . I LOVE that salsa!!!5 stars

    1. meggan

      Hey Julie! Thanks so much for your comment. I personally think Green Bean Casserole is MUCH better without the canned cream of soup. The real thing isn’t too hard to make, either! But I know what you mean, it’s hard to break tradition. :) Also, thanks for trying the Chipotle Guacamole! And the salsa! I appreciate you. :) Take care!

  6. Liz Randall

    How many people/servings does your recipe make? I like the idea of making your own mushroom sauce. I will be hosting approximately 30 people for Thanksgiving, so I want to have enough. THANKS.

    1. meggan

      Hey Liz! I tripled the recipe yesterday and it worked just great. I updated the blog post with the info (the increased ingredient amounts and instructions are in the recipe notes). If it’s easier, I can shoot you an email with the updated info. Just let me know! You just need a 5.5 quart stock pot AND a 6.5 quart slow cooker to accommodate the increase in ingredients. Please let me know if you have any questions! Thanks again!

    2. meggan

      Hi Liz! This recipe makes 8 to 10 servings. I feel like you could triple the recipe and be fine. I will test it out this weekend (tripling the recipe) and leave you another comment (and update the post) with any changes. I’ve been wanting to make this again anyway! Thanks for your question!

  7. Myra

    Can you use half-n-half in place of the heavy cream?

    1. meggan

      Myra, yes! Absolutely. That’s how my mom makes it. :) Thank you for your question!!

  8. Tish

    Love at first read! I love green bean casserole, so this tad bit healthier version was right up my alley. Next year I plan on makin my own fried onions. Two things I did add were sunflower kernals and cream cheese. YUMMY! Thanks so much for revamping an old classic!5 stars

    1. meggan

      Maybe just “a tad” bit healthier because not really. :D That’s awesome if you make your own fried onions, I just can’t do it. Not that hardcore. CREAM CHEESE?! Yes, oh yes. And even sunflower kernels sound amazing!!! Great ideas, thank you for sharing!

  9. I’ve actually never had green bean casserole before! I’m obsessed over how cheap green beans are so I’ve been trying to cook more with them haha. IF I wasn’t sold by the photos I was definitely pinning by the time you said this was the sexy julia roberts of food;)5 stars

  10. Oh, this is one of my favorite meals. Love it! Never made it in a crock pot though. Need to make is pretty soon.5 stars

  11. Oooh … delicious! I’ve said this before (a few times!) but I really am enjoying learning about your traditional foods. We don’t have anything like this over in the UK. We did have similar sorts of ‘bakes’ in the 80s/90s made with the Campbells thick soup, though, and I always loved it. Great to have a ‘real’ recipe for it and, for me, the piece de resistance is definitely those crispy onions. Mmm!5 stars

  12. Pauline

    We do not have cans of fried onions here in Australia, so what could I use instead??

    1. meggan

      Hi Pauline, making any kind of onion rings/onion strings from scratch would be the closest substitute, but that’s likely WAY too much work and kind of defeats the purpose of this recipe. Using crunchy, buttery bread crumbs is equally delicious.

      1. Preheat the oven to 350 degrees F/175 degrees C.
      2. Pulse 4 slices white sandwich bread (torn into quarters), 2 Tablespoons softened unsalted butter, 1/4 teaspoon salt, and 1/8 teaspoon pepper in a food processor until it resembles coarse crumbs (about 10 pulses).
      3. Spread the bread crumbs in an even layer on a rimmed baking sheet. Bake until lightly golden brown, about 10 to 15 minutes.
      4. Add them to the slow cooker right at the end, in place of the canned fried onions.
      5. You can make them ahead of time and store them in the refrigerator, but you may want to return them to the oven to warm up for a few minutes before you add them to the crock pot. Straight out of the fridge, obviously, they’d be cold.

      Thanks so much for your question! I will definitely update the recipe to include the bread crumbs option. If you have anymore questions, just let me know!

  13. Mary

    I don’t have a microwave. Would I just follow the stovetop cooking instructions on the package for the frozen beans? Or I am wondering if I could just defrost them overnight in the refrigerator, drain any extra water and add to the sauce. Won’t the crockpot cook them sufficiently without the extra step?

    1. meggan

      Hi Mary, thanks for your question! I think you could do either. The main point of cooking them/thawing them ahead of time is to get rid of the excess water.  I tried putting them in the crockpot straight from the freezer, and they watered down the sauce in the process. So, either cooking them on the stove top or thawing them overnight (and draining well in either case) should do the trick. Thanks for your question and I’ll add some notes about this in the post so it’s clear for everyone else!

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