This Crockpot Green Bean Casserole is everything that a green bean casserole can and should be (creamy, appropriately al dente, with a from-scratch flavor and addictively crunchy top) and exactly nothing that it shouldn’t be (mushy, overcooked to the point of destruction, bland).
A legitimately tasty version of a time-honored side made easy in the slow cooker, this is the green bean casserole we all need!
I came to green bean casserole late in life.
After years of wondering how it became a seemingly obligatory part of Thanksgiving (why waste space on an overcooked casserole when you can pack in the Cornbread Stuffing, Healthy Sweet Potato Casserole, or any of these Thanksgiving recipes instead?), I finally decided to cook it myself and see if I could come up with a green bean casserole that merited its spot on the plate.
Guess what? I BELIEVE.
This Healthy Green Bean Casserole showed me the possibilities and is now mandatory in my personal Thanksgiving lineup.
- Today’s recipe is a slow cooker adaptation.
- I made a few tasty tweaks based on your feedback (like turning it into a crockpot green bean casserole with cheddar cheese—so good!).
- I streamlined the prep process so that you don’t have to blanch the green beans in advance.
Outsourcing side dishes to the slow cooker is a pro-holiday move.
No matter the size of the gathering, we always run out of oven space and the slow cooker is a brilliant solution!
Look to recipes like these Crockpot Scalloped Potatoes, this Crock Pot Stuffing, or this gluten free Crockpot Wild Rice Stuffing to free up your oven.
Plus, the inherent make-ahead nature of the crock pot will make the day of less stressful too.
How to Make The Best Crockpot Green Bean Casserole
This slow cooker green bean casserole recipe breaks down into three key parts: the green beans, the creamy gravy, and the topping. Let’s explore.
Part 1: The Green Beans
When it comes to the green beans for green bean casserole, you have three choices: fresh, frozen, or canned.
- Fresh Green Beans. THE ONE YOU WANT. Fresh green beans are far less likely to overcook even after hours in the crockpot and have a crisp, delicious flavor. Trimming fresh green beans is quite possibly my least favorite kitchen task, and I am telling you, it is worth doing for fresh green bean casserole.
- Frozen, Cut Green Beans. The next best option. If you’d like to save some time, you can purchase a bag of cut, frozen green beans. Steam them according to the package instructions and pat them very dry before adding them to the slow cooker. They will be a little mushy, but certainly not inedible.
- Canned Green Beans. AVOID. Canned green beans will make your casserole mushy and inflict a metallic, stale flavor. If you haven’t liked green bean casserole in the past, the recipe likely used canned green beans. Green bean casserole is better with fresh green beans (or frozen), not canned.
While some crockpot fresh green bean casseroles call for blanching the green beans before adding them to the slow cooker, to me this took away the slow cooker’s ease.
After some playing around, I found by cutting the green beans into 1-inch pieces, I could cook them directly in the slow cooker without steaming or blanching. The green beans softened nicely, and we didn’t have any problems with hard pieces.
Part 2: The Creamy Mushroom Filling
Here, you have two options: canned cream of mushroom soup mixture (like the Campbell’s crockpot green bean casserole recipe), or an easy homemade mushroom filling.
As with trimming green beans, making the creamy sauce for green bean casserole from scratch is 100% worth it!
This mushroom filling is easy, luscious, and anything but bland.
- To keep this a healthy green bean casserole crockpot recipe, I skipped the cream/half-and-half and used regular milk. The filling still tasted rich and just the right amount of decadent.
- A splash of sherry vinegar and a touch of nutmeg make this filling shine. I had a hard time stopping myself from eating it right out of the pan!
- I took a note from some classic Midwest versions of this recipe and your comments and made this a crockpot green bean casserole with cheese. I stirred cheddar cheese into it at the end. DELISH.
Part 3: The Topping
While I’m proud about making these crock pot green beans from scratch, there was one store-bought ingredient that my taste testers actually preferred: the canned French fried onions.
I skipped stirring the onions into the casserole and used sauteed fresh onions in the filling instead, but for the topping, the salty, crispy crunch hit the spot.
The Directions
- Trim and cut the green beans. Add them to a slow cooker. 6-quart is best to ensure even cooking.
- Sauté the onion and mushrooms in butter.
- Stir in the flour, and cook for a couple minutes.
- Pour in the milk slowly, stirring constantly. Add the spices. Cook and stir until bubbly. Add the vinegar.
- Pour the sauce over the beans.
- Stir to coat. Cook on LOW for 3 to 5 hours. Just before serving, add the cheese. Top with crispy onions. DIG IN!
Storage Tips
- 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 degrees 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 (if using), but the casserole will still taste delicious.
Make Ahead Tips
Prepare the mushroom sauce up to 1 day in advance, and place it in an airtight 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 mix up green bean casserole the night before too. 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.
Leftover Ideas
Turn this leftover crock pot green bean casserole recipe into a hearty main dish by stirring in some leftover turkey, ham, or chicken before reheating.
What to Serve with Green Bean Casserole
Recommended Tools to Make this Recipe
- Slow Cooker. This one switches to “warm” to deter overcooking.
- Saucepan. You’ll use this kitchen tool on repeat.
- Measuring Spoons. Since these are double-sided, you’ll have less to wash after you make this cheesy green bean casserole.
The Best Slow Cooker
I have used this kitchen appliance for everything from soups to casseroles to desserts. It’s ideal for hands-free cooking!
Frequently Asked Questions
If your casserole is soupy, it’s likely because there was excess water in your ingredients. If you’re washing them first, sure you allow the green beans and mushrooms to dry completely before you begin the recipe. Also, a soupy green bean casserole could mean there wasn’t enough flour added.
To rectify a soupy casserole situation, try adding in extra flour. Start with just a little, then add more if needed. It’s also important to note that green bean casserole will thicken as it cools, so if your casserole isn’t too soupy, you may want to let it sit awhile to see if that helps.
I have not tried to make this recipe vegan, but if you want to experiment, you’ll need to use a dairy-free milk, cheese, and butter.
This is not a gluten free crockpot green bean casserole as written. However, I think you could swap the all-purpose flour for a 1:1 gluten free flour to make it gluten free. Be sure to check your fried onions too.
As far as green bean casserole goes, this recipe is relatively healthy. It’s packed with fiber, vitamin C, and protein from the green beans, and the cheese brings some calcium. Dig in and enjoy!
Crockpot Green Bean Casserole
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 black pepper
- 1/8 teaspoon ground nutmeg
- 1 tablespoon sherry vinegar
- 1 cup shredded cheddar cheese or gruyere cheese*
FOR THE TOPPING:
- 1 1/2 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 upon 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 degrees 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
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Looks great and I don’t have to juggle oven management! Would a plant-based milk work in this recipe?
Jenny, I think you could experiment with almondmilk, but just a heads up that your sauce will not be as thick and creamy. I’ve only tested it (and thus can only 100% recommend the recipe) with regular milk. If you do decide to play around though, I’d love to hear how it goes!
I very much appreciate this recipe for so many reasons! No canned soup! No oven space required. Great fresh flavor. Make ahead options! I did use my Instant Pot on Slow Cook mode and it did 5 hours. I opted to make the sauce the day before and toss it into the Cooker with the chopped green beans, stir and cook. This dish was a total hit. One guest said she thought she didn’t like green bean casserole but has now changed her mind! The fried onion topping was a must for this crowd. Yay!
Hi Joan! So glad you enjoyed the recipe! Thank you for this kind review!
I’m wondering why you suggest steaming frozen beans according to the package directions instead of just letting them thaw and drop them into the slow cooker? Would it seem like it would yield a result closer to using fresh beans? (I have a pound of fresh and, rather than running back into town to the grocery store, I figure I can just supplement it with a pound of frozen.)
Also, any thoughts about subbing fresh pearl onions for the onions in the recipe? My son-in-law doesn’t like onions. (It’s a texture thing, not a taste thing.) He can more easily remove the pearl onions… I’ve not really used pearl onions before so I’m unsure about how to go about subbing them… I welcome any suggestions you have…
Hi Mark! I haven’t tried making the beans the way you suggest, but you could experiment with it if you prefer. I think you could swap in pearl onions, but it will change the texture of the casserole a bit. I’d love to hear how it goes if you try it!
Follow up… The pearl onions worked quite well, although next time I would save some work and use frozen (the extra step of boiling the raw pearl onions isn’t really worth it). I added crumbled bacon because, well… bacon. Subbed corn starch for the flour because my daughter is gluten intolerant.
The gruyere cheese is what really makes this recipe, I think. I was lucky in that I had a half pound of it in my refrigerator looking for a use. I love cheddar but think gruyere makes this unique among green bean casseroles that I’ve tried.
We had planned on a socially distanced Thanksgiving meal on the front porch but my daughter was afraid she had been exposed to the virus so we postponed a week. (Testing later showed she wasn’t but file it under better safe than…) As the following Thursday was much colder, we met for a walk in the woods, returned to our house for pie on the porch and sent the two kids and their spouses home with prepackaged Thanksgiving dinners. Not optimal but that’s life in the age of C.
I’m so happy that you enjoyed the recipe, Mark! Thank you for reporting back and sharing this kind review!
Happy Thanksgiving Eve, Erin! The past several months have taught me to embrace the ingredients I have, but I do not want to make a cooking mistake with a new recipe tomorrow. May I omit the cheese? May I use balsamic or white balsamic vinegar? Thank you for your guidance.
Hi Amy! I”m so pleased to hear you are enjoying trying new things. I love this most with the cheese, but you can omit it if you truly prefer; it will be a little less creamy and rich. If you do not have sherry vinegar, I think white balsamic will work or you can simply omit it. I hope you enjoy it!
omg the mushroom sauce was AMAZING!!! So much better than canned condensed soup. Thanks for a great spin on on old classic. It was delicious. Still used French’s french fried onions though ;)
Also I used red wine vinegar and it was great.
I’m so happy that you enjoyed it, Stella! Thank you for sharing this kind review!
So many great tips, so well thought out! The family loved it. Will use again next year!
I’m so happy that you enjoyed it, Richard! Thank you for sharing this kind review!
This recipe was fantastic! I made it vegan by skipping the butter and using only oil, swapped dairy milk for Almond milk and vegan cheddar. It was unreal! Everyone loved it. Thank you so much! My sister hasn’t had green bean casserole in years and was so happy!
I’m so happy that you enjoyed it, Lauren! Thank you for sharing this kind review!
Had this on Thanksgiving after doing the prep ahead steps to help make day-of easier. It was delicious!!
I’m so happy that it was a hit, Megan! Thank you for sharing this kind review!
I made this casserole on Thanksgiving and it was delicious! I made it with white sharp cheddar cheese and used a can of store bought fried onions. This was an easy and delicious side and I will definitely be making it with other holiday meals in the future! Thank you for this awesome recipe!
I’m SO happy that you enjoyed it, Z! Thank you for sharing this kind review!
I’m slightly confused about making this ahead of time and freezing. Do I make the whole recipe, cook it, let it cool and freeze, and reheat in crock pot?
Hi Janet! 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. Rewarm leftovers in a baking dish in the oven at 350 degrees F. Hope this helps!