Crockpot Green Bean Casserole (Easy Slow Cooker Thanksgiving Side)
This crockpot green bean casserole is the holiday side that takes care of itself while the oven handles everything else. Long, tender green beans soak up a savory mushroom sauce for a few hours, then a thick layer of crispy onions goes on right before it reaches the table, so every spoonful is creamy underneath and crunchy on top. It is the dish people circle back to for seconds, and it never competes with the turkey for oven space.
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To make green bean casserole in the crockpot, you sauté mushrooms and onion, stir them into a seasoned cream of mushroom sauce with frozen green beans and some of the fried onions, then cook it on HIGH for 2½-3 hours or LOW for 4-5 hours. The two things that decide whether this slow cooker green bean casserole works are cooking the moisture out of the mushrooms first and saving most of the crispy onions for serving time. The beans go in straight from the bag, so it takes about 3 hours from start to finish on HIGH.
Jump to:
- Why You'll Love This Crockpot Green Bean Casserole
- Pin It for Later
- Ingredients and Substitutes
- How to Make Green Bean Casserole in the Crockpot
- How to Time Crockpot Green Bean Casserole for Thanksgiving Dinner
- What to Serve With This Slow Cooker Green Bean Casserole
- Crockpot Green Bean Casserole FAQs
- Crockpot Green Bean Casserole
Why You'll Love This Crockpot Green Bean Casserole
- It frees up the oven. The slow cooker handles the casserole, so the oven stays open for the turkey, the rolls and the pies. That alone makes it the easiest Thanksgiving side dish on the menu.
- The beans go in frozen. There is no thawing, trimming or blanching, which saves real time on the busiest cooking day of the year.
- It tastes like the classic. This is a classic green bean casserole at heart, and sautéed fresh mushrooms make this homemade green bean casserole in the crockpot taste deeper and more savory than the soup alone.
- The crunch survives. Onions stirred into the sauce season every bite, and the fresh layer added at the end stays crisp.
- It is a green bean casserole for a crowd. One batch serves ten as a side, which covers most holiday tables, and it is an easy vegetable side dish to make again on a weeknight.
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Ingredients and Substitutes
Amounts are in the recipe card. These are the ingredients that matter most.
- Frozen whole green beans: Whole beans hold their shape through a long cook, and they go in straight from the bag. They release liquid as they cook, so the sauce starts out thick on purpose.
- Fresh mushrooms: Cremini have more flavor, but white button mushrooms work too. I sauté them first to cook off some of their moisture, since nothing evaporates once the lid is on.
- Cream of mushroom soup: Condensed soup keeps these green bean casserole crockpot staples simple, which is what I want from a slow cooker side dish. Ready-to-eat soup makes the sauce too thin, and reduced-sodium soup works if you salt to taste.
- French-fried onions: I stir some in for onion flavor in every bite and save the rest so the topping stays crisp. A single container is enough for both.
- Worcestershire sauce: It adds the savory depth that canned soup is missing. Regular Worcestershire contains anchovies, so use a vegetarian brand when you need to.
How to Make Green Bean Casserole in the Crockpot
Every step is in the recipe card below. What helps most is knowing what each stage should look like.
- Sauté: The mushrooms are ready when they have released their liquid and started to brown, which takes 6-8 minutes, and the onion is soft.
- Stir: The frozen green beans go in straight from the bag, along with the sauce, the sautéed vegetables and the first portion of fried onions.
- Slow cook: Cook it on HIGH for 2½-3 hours or LOW for 4-5 hours. Frozen beans release liquid, so I keep an eye on the sauce and start checking the beans early in that window so they stay tender instead of turning too soft.
- Fix a loose sauce: If the sauce still looks thin near the end, leave the lid slightly ajar for the last 20-30 minutes.
- Finish: Scatter the remaining fried onions and the parsley over the top right before serving.
How to Time Crockpot Green Bean Casserole for Thanksgiving Dinner
Work backward from the time you plan to eat.
- On HIGH: Start the casserole about 3 hours before dinner.
- On LOW: Start it about 5 hours ahead if you want it going early and out of your way.
- Hands-on time: Plan on about 15 minutes of sautéing and stirring, which fits easily into a busy holiday morning.
- Oven space: Running two or three crockpot side dishes for Thanksgiving keeps the oven free for the main event, and green bean casserole in the crockpot is one of the simplest Thanksgiving side dishes to hand over.
- Beyond Thanksgiving: The same plan works for Christmas dinner and potlucks, and these Friendsgiving food ideas have more easy holiday side dishes to host or bring.
What to Serve With This Slow Cooker Green Bean Casserole
This side fits into a full holiday spread or a simple Sunday dinner. These pair especially well:
- Make-ahead mashed potatoes: This million-dollar version also finishes in the crockpot, so two sides are covered without touching the oven.
- Slow cooker creamed corn: Sweet, creamy corn balances the savory mushroom sauce and rounds out a lineup of crockpot vegetable side dishes.
- Sourdough stuffing: This make-ahead Dutch oven stuffing can bake while the green beans cook.
- Pumpkin-shaped dinner rolls: Soft rolls are perfect for mopping up the extra sauce, and these are shaped without any string.
- Baked brown sugar pineapple ham: A sweet glazed ham sets off the creamy green beans, which makes this pairing a natural choice for Christmas dinner.
- Meatless stuffed acorn squash: This makes a vegetarian centerpiece for the table when you use vegetarian Worcestershire in the casserole.
Crockpot Green Bean Casserole FAQs
For a family gathering, I plan to cook the casserole on the day rather than leave it assembled in the fridge overnight. You can still get ahead by sautéing the mushrooms and onion the day before and refrigerating them, so on the day itself the casserole is a quick stir before it goes into the slow cooker.
This recipe is built around frozen green beans, and I stick with them because they keep things simple. Canned beans are already fully cooked and turn soft over a long cook, while fresh beans need more time to become tender, so either one needs adjustments to the timing and the liquid.
The Warm setting works for holding the casserole while everyone fills their plates. I would not leave it on Warm for an extended period without checking that it stays at a safe temperature of 140°F or higher, so keep an instant-read thermometer handy.
Refrigerate leftovers in an airtight container for up to 3-4 days, then reheat them in the microwave or in a covered dish in a 350°F oven until hot. The topping softens in the fridge, so sprinkle on a handful of fresh fried onions after reheating to bring the crunch back.
Once the holidays wind down, this crockpot green bean casserole is just as useful on a regular weeknight, and these fall casseroles offer plenty of other cozy dinners that come together with little effort.
If you tried this Crockpot Green Bean Casserole Recipe or any other recipe on my website, please leave a 🌟 star rating and let me know how it went in the 📝 comments below.
Equipment
Ingredients
- 2 16-ounce bags frozen whole green beans
- 2 10.5-ounce cans condensed cream of mushroom soup
- ⅓ cup whole milk
- 8 ounces mushrooms (cremini or white button) sliced
- ½ medium yellow onion finely diced
- 1 tablespoon butter
- 1 tablespoon Worcestershire sauce
- ½ teaspoon garlic powder
- ½ teaspoon onion powder
- ¼ teaspoon black pepper
- ¼ teaspoon salt or to taste
- 1 6-oz container French-fried onions
- 2 tablespoons fresh parsley chopped
Instructions
- Melt 1 tablespoon of butter in a large skillet over medium heat.
- Add the mushrooms and onion and cook for 6-8 minutes, stirring occasionally, until the mushrooms release their moisture and start to brown and the onion is soft. Let them cool slightly.
- In a large bowl, whisk together the soup, milk, Worcestershire sauce, garlic powder, onion powder, pepper and salt.
- Stir in the frozen green beans, the sautéed mushrooms and onion, and 1 cup of French-fried onions until evenly coated.
- Transfer the mixture to a greased 6-quart slow cooker and cover.
- Cook on HIGH for 2½-3 hours or on LOW for 4-5 hours, until the beans are tender and the sauce is bubbling at the edges. Start checking the beans near the beginning of the time window so they do not turn too soft.
- For extra crunch, warm the remaining French-fried onions in a dry skillet over medium heat for 1-2 minutes.
- Sprinkle the remaining French-fried onions and the parsley over the casserole just before serving.
Notes
- No thawing needed: Add the green beans straight from the freezer. Whole frozen beans hold their shape better than short cut beans over a long cook.
- Watery sauce: Frozen beans release liquid as they cook. If the sauce looks loose near the end, leave the lid slightly ajar for the last 20-30 minutes.
- Crispy topping: Add the topping just before serving. Onions added at the start soften in the sauce.
- Holding on Warm: The Warm setting is fine while serving, but check that the casserole stays at 140°F or higher.
- Make ahead: Cook the casserole on the day you serve it. You can sauté the mushrooms and onion a day ahead and refrigerate them.
- Leftovers: Refrigerate in an airtight container for up to 3-4 days. Reheat in the microwave or a covered dish at 350°F, then top with fresh fried onions.
- Vegetarian: Regular Worcestershire sauce contains anchovies. Use a vegetarian Worcestershire sauce to make this vegetarian.
- Gluten: Condensed soup and French-fried onions usually contain wheat, so this recipe is not gluten-free as written.