Slow Cooker Green Bean Casserole
Green bean casserole is one of those dishes that never goes out of style, especially around the holidays. This slow cooker version keeps your oven free and your stress low. You get tender green beans, a creamy sauce, and just the right amount of savory flavor.
It’s simple to prep, easy to scale, and forgiving—perfect for busy cooks. Whether you’re hosting or bringing a dish to share, this one delivers every time.
Why This Recipe Works
This slow cooker method takes the pressure off the oven and keeps the casserole warm without drying it out. The low-and-slow approach lets the flavors meld together while keeping the green beans tender but not mushy.
Using a combination of condensed soup, broth, and sour cream gives the sauce a rich, velvety texture. A final stir and topping at the end keeps the crispy onions crunchy instead of soggy. It’s the kind of set-it-and-forget-it recipe that still tastes thoughtfully made.
Ingredients
- 2 pounds fresh green beans, trimmed and cut into 2-inch pieces (or use 2 pounds frozen, thawed and drained)
- 2 cans (10.5 ounces each) condensed cream of mushroom soup
- 1/2 cup low-sodium chicken or vegetable broth
- 1/2 cup sour cream (or plain Greek yogurt)
- 1 small onion, finely chopped
- 2 cloves garlic, minced
- 1 teaspoon kosher salt (adjust to taste)
- 1/2 teaspoon black pepper
- 1/2 teaspoon onion powder (optional, for extra savory depth)
- 1/4 teaspoon ground nutmeg (optional, classic with creamy mushroom flavors)
- 1 1/2 cups crispy fried onions, divided
- 1 cup shredded cheddar cheese (optional, for a cheesier version)
- 1 tablespoon unsalted butter (optional, for sautéing aromatics)
- Nonstick spray or a slow cooker liner
How To Make This Slow Cooker Green Bean Casserole
- Prep the slow cooker: Lightly coat the insert with nonstick spray or use a liner.
This prevents sticking and makes cleanup easier.
- Blanch the green beans (optional but recommended for fresh): Boil a large pot of salted water. Add fresh green beans and cook for 3–4 minutes until bright green and just tender. Drain and rinse under cold water to stop the cooking.
If using frozen beans, thaw and pat dry instead.
- Sauté aromatics (optional for extra flavor): In a small skillet, melt butter over medium heat. Cook the chopped onion with a pinch of salt for 3–4 minutes until soft. Stir in garlic for 30 seconds.
This step adds a mellow, sweet base.
- Mix the sauce: In a large bowl, whisk together the condensed cream of mushroom soup, broth, sour cream, salt, pepper, onion powder, and nutmeg. If you’re using cheese, stir in half of it now.
- Combine in the slow cooker: Add the green beans, sautéed onion mixture (if using), and 1/2 cup crispy fried onions to the slow cooker. Pour the sauce over and toss to coat evenly.
- Cook low and slow: Cover and cook on Low for 4–5 hours or on High for 2–3 hours, until the beans are tender and the sauce is bubbling around the edges.
- Finish and crisp: Stir the casserole to re-coat everything in the sauce.
If using cheese, sprinkle the remaining cheese over the top, cover, and cook for 10–15 minutes until melted.
- Add the crunchy topping: Right before serving, sprinkle the remaining crispy fried onions over the casserole. Cover for 5 minutes with heat off to warm them slightly without softening.
- Serve warm: Switch the slow cooker to Warm if serving over a long period. Keep extra crispy onions on the side for topping.
Storage Instructions
- Refrigerator: Store leftovers in an airtight container for up to 4 days.
- Freezer: Freeze without the crispy onion topping for up to 2 months.
Thaw overnight in the fridge before reheating.
- Reheating: Reheat in a 325°F oven until hot and bubbly (about 20–25 minutes), or microwave in short bursts, stirring occasionally. Add fresh crispy onions after reheating to maintain crunch.
Why This is Good for You
Green beans bring fiber, vitamin C, vitamin K, and antioxidants to the table. Cooking them gently helps keep their texture and some nutrients intact.
Compared to heavy, oven-baked versions, this recipe can be lighter if you use low-sodium soup and broth and swap sour cream for Greek yogurt. You still get a satisfying, creamy dish with fewer calories and less salt when you adjust the ingredients. It’s a comfort classic with a little more balance.
What Not to Do
- Don’t add the crispy onions too early. They’ll steam and go soggy.
Save them for the very end.
- Don’t skip seasoning. Taste the sauce before cooking. Condensed soup varies in salt—adjust to your preference.
- Don’t overcook. Past 5 hours on Low, fresh beans can turn mushy. Check early the first time you make it.
- Don’t overload the slow cooker. More than three-quarters full can lead to uneven cooking.
- Don’t add extra liquid without reason. The beans release moisture.
Too much broth will thin the sauce.
Alternatives
- Mushroom swap: Use cream of chicken or cream of celery soup if you prefer a different flavor.
- Make it from scratch: Skip condensed soup. Whisk 2 tablespoons butter and 2 tablespoons flour in a saucepan to make a roux, add 1 1/2 cups milk and 1/2 cup broth, simmer until thick, and stir in 1 cup sautéed mushrooms. Season to taste and use in place of the canned soup mixture.
- Dairy-light: Use Greek yogurt instead of sour cream, or try a dairy-free yogurt.
Choose dairy-free condensed soup for a fully dairy-free version.
- Gluten-free: Use gluten-free condensed soup and gluten-free crispy onions. Check broth labels, too.
- Extra veggie boost: Stir in sautéed mushrooms, diced bell pepper, or chopped cooked bacon for smoky depth.
- Cheesy twist: Add shredded cheddar, Gruyère, or Parmesan for a richer, more indulgent casserole.
- Fresh herb finish: Sprinkle with chopped parsley, chives, or thyme for brightness.
FAQ’s For Slow Cooker Green Bean Casserole
Can I make this ahead?
Yes. Assemble the casserole without the crispy onions, cover, and refrigerate up to 24 hours. Cook as directed, adding 30–45 minutes if starting from cold. Top with crispy onions right before serving.
Do I have to blanch the green beans?
No, but blanching helps lock in color and keeps them from turning too soft. If you skip it, choose the lower end of the cook time and check early for doneness.
Can I use canned green beans?
You can, but they’re softer and cook much faster. If using canned (well-drained), cook on Low for 1–2 hours, just until heated through and bubbly, to avoid mushiness.
How do I keep it warm for a party?
Once cooked, switch the slow cooker to Warm and leave the lid slightly ajar to reduce condensation. Add the crispy onions at serving time and replenish as needed.
What if my sauce is too thin?
Stir in 2–3 tablespoons of cream cheese or a slurry of 1 teaspoon cornstarch mixed with 2 teaspoons cold water. Cover and cook on High for 10–15 minutes until thickened.
What size slow cooker should I use?
A 5- to 6-quart slow cooker works well for this recipe. If you’re doubling it, use a large oval 7- to 8-quart model and extend the cook time slightly.
How can I reduce the sodium?
Use low-sodium broth, low-sodium condensed soup, and skip added salt until the end. Taste and season lightly before serving.
Can I make it vegetarian?
Absolutely. Use vegetable broth and a mushroom-based condensed soup. Everything else stays the same.
In Conclusion
Slow Cooker Green Bean Casserole is the kind of dish that takes care of itself while you focus on the rest of the meal. It’s creamy, savory, and familiar, with a reliable crunch right at the end. The method is simple, the ingredients are flexible, and the results are consistently great.
Keep this version in your back pocket for holidays, potlucks, and any night you want easy comfort without the oven shuffle.
Slow Cooker Green Bean Casserole
Ingredients
- 2 pounds fresh green beans, trimmed and cut into 2-inch pieces (or use 2 pounds frozen, thawed and drained)
- 2 cans (10.5 ounces each) condensed cream of mushroom soup
- ½ cup low-sodium chicken or vegetable broth
- ½ cup sour cream (or plain Greek yogurt)
- 1 small onion, finely chopped
- 2 cloves garlic, minced
- 1 teaspoon kosher salt (adjust to taste)
- ½ teaspoon black pepper
- ½ teaspoon onion powder (optional, for extra savory depth)
- ¼ teaspoon ground nutmeg (optional, classic with creamy mushroom flavors)
- 1 1/2 cups crispy fried onions, divided
- 1 cup shredded cheddar cheese (optional, for a cheesier version)
- 1 tablespoon unsalted butter (optional, for sautéing aromatics)
- Nonstick spray or a slow cooker liner
Instructions
- Prep the slow cooker: Lightly coat the insert with nonstick spray or use a liner. This prevents sticking and makes cleanup easier.
- Blanch the green beans (optional but recommended for fresh): Boil a large pot of salted water. Add fresh green beans and cook for 3–4 minutes until bright green and just tender. Drain and rinse under cold water to stop the cooking. If using frozen beans, thaw and pat dry instead.
- Sauté aromatics (optional for extra flavor): In a small skillet, melt butter over medium heat. Cook the chopped onion with a pinch of salt for 3–4 minutes until soft. Stir in garlic for 30 seconds. This step adds a mellow, sweet base.
- Mix the sauce: In a large bowl, whisk together the condensed cream of mushroom soup, broth, sour cream, salt, pepper, onion powder, and nutmeg. If you’re using cheese, stir in half of it now.
- Combine in the slow cooker: Add the green beans, sautéed onion mixture (if using), and 1/2 cup crispy fried onions to the slow cooker. Pour the sauce over and toss to coat evenly.
- Cook low and slow: Cover and cook on Low for 4–5 hours or on High for 2–3 hours, until the beans are tender and the sauce is bubbling around the edges.
- Finish and crisp: Stir the casserole to re-coat everything in the sauce. If using cheese, sprinkle the remaining cheese over the top, cover, and cook for 10–15 minutes until melted.
- Add the crunchy topping: Right before serving, sprinkle the remaining crispy fried onions over the casserole. Cover for 5 minutes with heat off to warm them slightly without softening.
- Serve warm: Switch the slow cooker to Warm if serving over a long period. Keep extra crispy onions on the side for topping.
