Green Bean Casserole Classic (Printable)

Tender green beans in creamy mushroom sauce topped with crispy fried onions; ideal for holiday gatherings.

# What You’ll Need:

→ Vegetables

01 - 1 lb fresh green beans, trimmed and cut into 2-inch pieces or 1 lb frozen green beans, thawed
02 - 1 small yellow onion, finely chopped
03 - 2 cloves garlic, minced
04 - 8 oz cremini or button mushrooms, sliced

→ Sauce

05 - 2 tbsp unsalted butter
06 - 2 tbsp all-purpose flour
07 - 1 cup whole milk
08 - 1/2 cup low-sodium vegetable broth
09 - 1/2 cup sour cream
10 - 1/2 tsp salt
11 - 1/4 tsp black pepper
12 - 1/4 tsp ground nutmeg

→ Topping

13 - 1 1/2 cups crispy fried onions (store-bought or homemade)

# How-To Steps:

01 - Preheat the oven to 350°F.
02 - Bring a large pot of salted water to a boil. Add green beans and cook for 4 to 5 minutes until bright green and just tender. Drain and transfer immediately to an ice water bath to stop cooking. Drain again and set aside.
03 - In a large skillet over medium heat, melt butter. Add chopped onion and sauté for 2 to 3 minutes until softened. Add garlic and mushrooms and cook for an additional 5 minutes until mushrooms are tender and excess liquid evaporates.
04 - Stir in flour and cook, stirring constantly, for 1 minute. Gradually whisk in milk and vegetable broth, and cook, stirring, until the sauce thickens, about 3 to 4 minutes.
05 - Remove skillet from heat. Stir in sour cream, salt, black pepper, and ground nutmeg until the sauce is smooth.
06 - Add the drained green beans to the sauce and toss to coat evenly.
07 - Transfer the mixture to a greased 2-quart baking dish. Evenly sprinkle 1 cup of crispy fried onions over the top.
08 - Bake for 25 minutes until the casserole is bubbling. Remove from oven, sprinkle remaining crispy fried onions on top, and bake an additional 5 minutes until golden brown.
09 - Let the casserole rest for 5 minutes before serving.

# Expert Tips:

01 -
  • It comes together in under an hour, which means you can actually enjoy time with your guests instead of staying glued to the stove.
  • The combination of creamy sauce and those crispy fried onions creates a textural contrast that keeps every bite interesting.
  • It's the kind of dish that works for fancy dinners or casual weeknight meals without any apologies.
02 -
  • If you don't blanch the green beans first, they'll continue cooking in the oven and turn into mush; the ice bath stops that immediately.
  • Adding the sour cream off the heat prevents it from breaking and ensures a smooth, luscious sauce.
  • Save some fried onions for topping at the last minute—the ones mixed into the dish early get soft and disappear.
03 -
  • Let the casserole rest for 5 minutes before serving so it holds together beautifully when you scoop.
  • If you're doubling the recipe for a crowd, use a 3-quart baking dish and add about 10 minutes to the baking time.
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