This modern slow cooker adaptation of the classic green bean casserole transforms the traditional Thanksgiving side dish into an effortless year-round favorite. The slow cooking process allows the flavors to meld beautifully, creating a rich, creamy texture that pairs perfectly with the crispy onion topping.
Why This Recipe Works
I’ve discovered that using the slow cooker for this beloved casserole not only frees up valuable oven space but also allows the green beans to gradually absorb all the savory flavors while maintaining their texture. The combination of cream of mushroom soup and onion soup mix creates an umami-rich base, while the mozzarella cheese adds a wonderful stretchy, creamy element that sets this version apart from traditional recipes.
Ingredients
Base Ingredients:
- 4 cans (14.5 oz each) green beans, drained (1.64 kg / 58 oz total)
- 2 cans cream of mushroom soup (605g / 21.3 oz)
- 1 cup whole milk (240ml / 8 fl oz)
- 2 cups shredded mozzarella cheese (200g / 7 oz)
- 1 packet onion soup mix (28g / 1 oz)
- 1 teaspoon garlic powder
- ½ teaspoon black pepper
Topping:
- 2 cups french-fried onions (170g / 6 oz)
Instructions
- Prepare the Slow Cooker
- Lightly grease a 6-quart slow cooker with cooking spray
- This prevents sticking and makes cleanup easier
- Combine Base Ingredients
- Drain green beans thoroughly in a colander
- In the slow cooker, combine drained green beans, cream of mushroom soup, and milk
- Stir in shredded mozzarella cheese, onion soup mix, garlic powder, and black pepper
- Mix until ingredients are evenly distributed
- Cook
- Cover and cook on LOW for 4-5 hours or HIGH for 2-3 hours
- The casserole is ready when it’s heated through and bubbly around the edges
- Add Topping
- During the final 30 minutes of cooking, spread french-fried onions evenly over the top
- Replace lid and continue cooking until onions are lightly toasted
- Finish and Serve
- Once done, remove from heat
- Let stand for 10 minutes before serving
- This allows the casserole to set slightly for easier serving
Storage and Make-Ahead Tips
- Store leftovers in an airtight container in the refrigerator for up to 3 days
- The fried onions will lose their crunch in storage, so consider adding fresh ones when reheating
- For best results, reheat in the oven at 350°F (175°C) for 15-20 minutes
Nutrition Information
(Per serving, based on 10 servings)
- Calories: 285
- Total Fat: 17g
- Saturated Fat: 6g
- Cholesterol: 20mg
- Sodium: 890mg
- Total Carbohydrates: 26g
- Dietary Fiber: 3g
- Protein: 9g
Recipe Notes
- Don’t lift the slow cooker lid during cooking as this releases essential heat and moisture
- For extra flavor, add ½ cup grated Parmesan cheese with the mozzarella
- Fresh green beans can be substituted for canned – blanch them first for 3 minutes
- For a crispier topping, transfer to a baking dish and broil for 1-2 minutes before serving
- Cut green beans into smaller pieces if preferred for easier serving
This slow cooker green bean casserole offers all the comfort of the traditional version with the convenience of hands-off cooking. The combination of creamy sauce, tender green beans, and crispy onion topping creates a satisfying side dish that’s perfect for holidays, potlucks, or any family gathering. The slow cooking process ensures that every bite is infused with flavor, while the final addition of crispy onions provides the perfect textural contrast.
