Classic Green Bean Casserole Recipe

Classic Green Bean Casserole Recipe

This classic green bean casserole skips the canned soup and builds its creamy mushroom sauce from scratch — and the difference is worth every minute. Fresh green beans stay bright and tender-crisp under a silky sauce of sautéed mushrooms, onion, and garlic, and the whole thing is crowned with a thick layer of crispy fried onions that go golden and crunchy in the oven. It is the Thanksgiving side dish that regulars ask about before they even sit down.

Because the sauce comes together in the same skillet the casserole bakes in, cleanup stays minimal on a day when the kitchen is already at full capacity. And like most great holiday sides, it can be assembled a day ahead and baked just before dinner.

This recipe is part of our Thanksgiving collection — the turkey, every classic side, the pies, and a day-by-day plan for getting it all to the table.

Prep time: 20 minutes Cook time: 35 minutes Servings: 8

What You’ll Need

• Large oven-safe deep skillet with a lid, or a 9×13-inch baking dish
• Large pot for blanching
• Colander
• Large bowl of ice water
• Wooden spoon

For a pan that goes from stovetop to oven, see our best oven-safe deep skillets with lids guide.

Ingredients

• 1½ pounds fresh green beans, trimmed and halved
• 2 tablespoons unsalted butter
• 8 ounces cremini mushrooms, sliced
• 1 small yellow onion, finely diced
• 2 cloves garlic, minced
• 3 tablespoons all-purpose flour
• 1½ cups whole milk
• 1 cup low-sodium chicken or vegetable broth
• 1 tablespoon soy sauce
• 1/2 teaspoon fine sea salt
• 1/4 teaspoon freshly ground black pepper
• 1/8 teaspoon ground nutmeg (optional)
• 1 can (6 ounces) crispy fried onions, or about 1½ cups

Instructions

1. Blanch the green beans. Bring a large pot of salted water to a boil. Add the green beans and cook for 4–5 minutes, until bright green and just tender. Drain and immediately transfer to a large bowl of ice water to stop the cooking, then drain again and pat dry.
2. Sauté the mushrooms and onion. Melt the butter in a large oven-safe deep skillet over medium-high heat. Add the mushrooms and cook, without stirring too often, for 5–6 minutes until browned. Add the onion and cook for 3–4 minutes more until softened, then stir in the garlic and cook for 1 minute until fragrant.
3. Make the sauce. Sprinkle the flour over the vegetables and stir for 1 minute to cook off the raw flour taste. Gradually pour in the milk and broth, stirring constantly to avoid lumps. Add the soy sauce, salt, pepper, and nutmeg, and simmer for 3–4 minutes, stirring, until the sauce thickens enough to coat a spoon.
4. Combine with the beans. Add the blanched green beans to the skillet and toss until every bean is coated in sauce. Taste and adjust the salt if needed. (If you are using a baking dish instead of an oven-safe skillet, transfer the mixture to the dish now.)
5. Top and bake. Sprinkle the crispy fried onions evenly over the top. Bake at 350°F (175°C) for 20–25 minutes, until the sauce is bubbling around the edges and the onion topping is deeply golden.
6. Rest and serve. Let the casserole rest for 5 minutes before serving so the sauce thickens slightly. Serve warm.

Tips for the Best Classic Green Bean Casserole

• Do not overcook the beans in the blanch. They will cook again in the oven, so pull them while they still have a little bite. Five minutes in boiling water is plenty — the ice bath locks in their color and crunch.
• Let the sauce thicken before adding the beans. A sauce that coats a spoon will stay creamy in the oven; a thin one turns watery as the beans release moisture. If it looks too thin, simmer it another minute or two before combining.
• Make it ahead. Assemble the casserole (without the onion topping) up to a day in advance, cover, and refrigerate. On Thanksgiving Day, bake covered at 350°F (175°C) for 20 minutes, then uncover, add the fried onions, and bake 15 minutes more until bubbling and golden.

Creamy, crunchy, and unmistakably Thanksgiving — this green bean casserole earns its spot next to the herb butter roast turkey every year.

For the rest of the plate, see our Thanksgiving side dishes roundup.

Frequently Asked Questions

Can I assemble green bean casserole the day before?

Yes — make the sauce and combine it with the beans on Tuesday, cover and refrigerate. Keep the fried-onion topping off until Thursday so it stays crisp; it goes on for the last few minutes of baking.

Why are my green beans soggy?

They were overcooked before the casserole went in the oven. Blanch them just until bright green and still firm — they cook again in the sauce. Draining them well matters too; extra water thins the sauce and steams the beans.

Can I use canned green beans or canned soup instead?

You can, and generations of cooks have — but the from-scratch sauce in this recipe takes about ten extra minutes and tastes noticeably fresher. If you do swap, keep the seasoning gentle, because the canned versions bring more salt with them.