Slow Cooker Green Bean Casserole is an easy way to make a holiday favorite without taking up your oven space! All of the flavors your love in a traditional green bean casserole made with just 6 ingredients right in your slow cooker!
For more delicious Thanksgiving recipes, consider checking out my posts for a Perfect, Easy Thanksgiving Turkey, Candied Pecan Sweet Potato Casserole, and Cranberry Sauce.
Why This Recipe Works
Space-saving — I don’t know about you but when Thanksgiving comes at my house you basically have to be a designer and space planner to figure out how to get everything cooked and ready at the same time. This slow cooker green bean casserole is started four hours before you eat and then just sits out of sight to finish cooking. Heck, once it’s cooking you can put it anywhere to cook. I’ve been known to plug slow cookers in my kids’ bedrooms. Ha.
Good as the “real” thing — Now, you might be thinking there’s no way a slow cooker green bean casserole can be as good as the original recipe that you cook in. I, too, was a skeptic. But I’ve tested this twice now and it’s just as good! The beans don’t get mushy at all (so long as you go with fresh). Give it a try, I promise you’ll love it too.
Simple ingredients — The ingredients in this crock pot green bean casserole are easy to find and easy to incorporate. You probably have most of the ingredients already and it’ll just take one quick trip to the store to get fresh produce and French friend onions.
So easy — While you do need ot make the fresh mushroom soup mixture first from scratch, that can be started 4 hours ahead of dinner time. Plenty of time to turn your attention to all those other yummy Thanksgiving dishes. After you make the sauce for the green bean casserole recipe, you simple set it and forget it.
Ingredients
- Butter — I use unsalted butter and then add salt later to taste but if you prefer salted butter then that’s okay too.
- Baby Bella or cremini mushrooms — Purchase these mushrooms pre-sliced if you can find them that way. One less thing to do!
- Salt and cracked black pepper — I salt and pepper a little bit at a time to taste until I think it’s perfect, then set the timer to low for 4 hours.
- Garlic — I used the minced garlic in the jar but you can mince your own. Any name brand is fine.
- Flour — All-purpose white flour works best when making the roux for the mushroom sauce in this green bean casserole.
- Milk — Whatever milk you have in your fridge is just fine in this recipe.
- Heavy cream — Don’t skimp on the real heavy cream. Substituting extra milk will not be creamy enough. If your grocery is out of heavy cream you can use half and half.
- Nutmeg — Any brand of ground nutmeg is good in this recipe.
- Parmesan cheese — I purchase pre-shredded parmesan. Any kind will do. But if you want it to be extra creamy, grate parmesan from fresh.
- Fresh green beans — For simplicity, I use two 12 oz packs of green beans. But if you can’t find those, you can use 24 oz of fresh green beans and trim the ends.
- French fried onions — Hurry and go now to find the French fried onions. I’m always afraid these will be out of stock before Thanksgiving and stock up. Any brand is yummy.
Here’s How You Make It
- First, start the mushroom sauce by melting 1 tablespoon of the butter over a medium-high heat in a high-sided frying pan or a large saucepan. Once the butter is frothy, add the mushrooms and a pinch of salt, and cook until the mushrooms are soft and start to color. (photo 1)
- Next, add the minced garlic and stir, cooking for a few minutes more until the garlic starts to become aromatic. Then, season the mushrooms with black pepper, remove them from the pan, and set them aside. (not pictured)
- Now make the roux by melting the remaining 4 tablespoons of butter in the pan. To the butter, add the flour and whisk them together for a few minutes to remove the ‘raw’ taste from the flour. (not pictured)
- To the roux, gradually pour in the milk, whisking the whole time, until you have a smooth sauce. Keep cooking and whisking the sauce often, until it is thick enough to coat the back of a spoon. (photo 2)
- Take the sauce off the heat before stirring in the heavy cream, nutmeg, and shredded parmesan. Whisk this mixture again until it’s smooth. Add back the cooked mushrooms and season to taste with more salt and pepper, if needed. (photos 3-4)
- Cut the green beans in half so they fit in the slow cooker better and transfer them to the cooking insert. Stir in the mushroom sauce. (photo 5)
- Put the lid on the slow cooker green bean casserole and set to cook on low for 4 hours, or until the beans are tender but still retain a little bit of their crunch. (Depending on the size and shape of your slow cooker, you may need to stir occasionally during cooking to make sure the beans cook evenly.) (not pictured)
- Finally, top the casserole with the French onions just before serving. (photo 6)
First of all, make sure you follow the directions for making the mushroom soup correctly. Make that roux, whisking in the flour to the butter, then the milk into the flour/butter mixture, ensuring a smooth sauce that is thick enough to coat the back of a spoon. That’s how you know it’s done. If it doesn’t stick to the spoon, it’s not thick enough.
Another error people make when making this crockpot green bean casserole is that they substitute more milk for the heavy cream. Heavy cream is key to making the sauce thick.
Also, if you rinse your green beans, be sure to pat them dry to ensure no extra water gets in the slow cooker.
I always use fresh green beans in this green bean casserole recipe. Canned or frozen tend to get too soggy (and contribute to that runny casserole problem). You need the fresh beans to get that tender-crisp taste and bite when you eat them.
Expert Tips and Tricks
- This recipe halves perfectly for smaller slow cookers.
- Want to free up that stove space even more? If you have a sear-and-stew model of slow cooker or use the slow cooker setting of an Instant Pot, the mushrooms can be cooked and the sauce can be made in the cooking insert.
More Thanksgiving Recipes
- Stuffed Turkey Breast
- Traditional Baked Green Bean Casserole
- Thanksgiving Stuffing
- Garlic Mashed Potatoes
Did you make this recipe? AMAZING! Be sure to snap a photo and tag me on social, then come back here to rate the recipe!
Slow Cooker Green Bean Casserole
Ingredients
- 5 tablespoons butter
- 8 ounces baby bella or cremini mushrooms - sliced
- salt & cracked black pepper - to taste
- 4 teaspoons minced garlic
- 4 tablespoons flour
- 1 ½ cups milk
- ½ cup heavy cream
- ¼ teaspoon nutmeg
- 1 cup shredded parmesan cheese
- 1 ½ pounds fresh green beans - ends trimmed
- ½ cup French fried onions
Instructions
- Heat 1 tbsp of the butter over a medium high heat in a high sided frying pan or a large saucepan. Once the butter is frothy, add the mushrooms and a pinch of salt, and cook until the mushrooms are soft and starting to color.
- Add the garlic and cook for a few minutes more until aromatic. Season with black pepper, remove from the pan, and set aside.
- Melt the remaining 4 tbsp of butter in the pan. Add the flour, and whisk for a few minutes to remove the ‘raw’ taste from the flour.
- Gradually pour in the milk, whisking the whole time, until you have a smooth sauce. Keep on cooking, whisking often, until the sauce is thick enough to coat the back of a spoon.
- Remove from the heat before stirring in the heavy cream, nutmeg and shredded parmesan. Whisk until smooth, add the cooked mushrooms, and season to taste with more salt and pepper, if needed.
- Halve the green beans so that they fit in the slow cooker better, and transfer them to the cooking insert. Stir in the mushroom sauce.
- Cover and cook on low for 4 hours, or until the beans are tender but still retain a little bit of their crunch. Depending on the size and shape of your slow cooker, you may need to stir occasionally during cooking to make sure the beans cook evenly.
- Top the casserole with the French onions just before serving.
Yum!! This sounds so perfect for the holiday season 🙂 I love slow cooker recipes, they make life so much easier!
Dani | http://www.styledvariety.com
It looks yummy. I ‘ll make it this weekend.
What size crock pot did you use? Is 6.5 too big?
No that’s perfect!
This was really tasty. A bit watery but overall really good.
if we don’t care for mushrooms, is there a substitute?
This recipe hasn’t been tested for mushroom substitutes but you can just omit them entirely 🙂