How To Make Classic Green Bean Casserole

updated Oct 7, 2022

Learn how to make green bean casserole using the right grocery store shortcuts to rival the classic back-of-the-box recipe.

Serves8 to 10

Prep10 minutes

Cook25 minutes to 30 minutes

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(Image credit: Joe Lingeman)

“Classic” green bean casserole means different things to different people. For some, green bean casserole consists of frozen and canned ingredients, quickly tossed together and baked as the token green vegetable side dish for holiday dinners.

Others see green bean casserole as an opportunity to make every component from scratch, using only fresh green beans and making their own mushroom sauce and crispy fried onions. This is the new classic, a middle ground between convenience and comfort, without a sacrifice of quality or flavor.

Green Bean Casserole

The Best Green Beans for Green Bean Casserole

My mother always made green bean casserole with store-bought canned green beans because her mother made green bean casserole with canned green beans. But my grandmother’s canned green beans were picked and canned from her home garden.

When I make green bean casserole, I skip canned all together and head for the freezer instead because frozen green beans are the best green beans to use for green bean casserole.

Frozen green beans are blanched and flash-frozen, usually within a few hours of picking, which means they have their peak-season flavor preserved and don’t require any additional cooking before going into the casserole. Just be sure to thaw and drain the green beans before adding to the casserole — otherwise their excess moisture may thin the mushroom gravy.

Tip: Quickly thaw the green beans by placing them under running water in a colander. Let the beans drain while you prepare the rest of the casserole.

(Image credit: Joe Lingeman)

Making Mushroom Gravy for Green Bean Casserole

Old-school green bean casserole uses condensed mushroom soup as the sauce for the green beans. Historically, the marketing geniuses at Campbell’s and French’s were responsible for the popularity of green bean casserole at Thanksgiving.

Nothing against condensed mushroom soup, but we can make a simple mushroom sauce (technically a gravy) that is more flavorful, and not much more expensive, with just a few ingredients: mushrooms, butter, flour, milk, and broth. If you’ve made a pan gravy in the past, the steps are familiar, but if not, here a few keys to success.

  • Be patient with the mushrooms: Cook the mushrooms until they brown and release most of their moisture. Mushrooms have more water in them than you’d think. This takes about five minutes over medium-high heat.
  • Wait for the nutty smell: Sprinkle the flour over the mushrooms and cook until the flour smells nutty, stirring regularly. This will help thicken the sauce.
  • Keep stirring: Add the milk and broth slowly and stir while mixing to prevent lumps. Bring the whole thing to a simmer and make sure it thickens in the pan. Remember that it will continue to thicken as it cools.
  • A surprise ingredient: A teaspoon of soy sauce or tamari adds that super-savory flavor and color we expect from condensed mushroom soup. You can certainly skip it, but be sure to taste the gravy and add more salt if needed.

Make-ahead tip: Assemble the casserole without the crisp onion topping and store tightly wrapped in the refrigerator for up to three days. Remove from the refrigerator while the oven preheats. Top with the fried onions and bake.

(Image credit: Joe Lingeman)

French’s Fried Onions Are Simply the Best

Look, I have tried every method for making crispy onions for green bean casserole. I’ve tried rolling onion in breadcrumbs and roasting them. I’ve tempura battered and fried them. I’ve even tried dehydrating onions into a crispy state. Here’s the thing — no method comes close to the ease and flavor of the canned fried onions.

Beyond being more convenient, I’d argue that there is a historical precedent for using fried onions from a can, as they were included in the original Campbell’s recipe published in 1955.

How To Make Classic Green Bean Casserole

Learn how to make green bean casserole using the right grocery store shortcuts to rival the classic back-of-the-box recipe.

Prep time 10 minutes

Cook time 25 minutes to 30 minutes

Serves8 to 10

Nutritional Info


  • 4 tablespoons

    unsalted butter

  • 12 ounces

    white button or cremini mushrooms, sliced

  • 2 cloves

    garlic, minced

  • 1/4 cup

    all-purpose flour

  • 2 cups

    whole milk

  • 1 cup

    low-sodium chicken or vegetable broth

  • 1 teaspoon

    tamari or soy sauce

  • 1/2 teaspoon

    freshly ground black pepper

  • 1/2 teaspoon

    freshly grated nutmeg

  • 2 (6-ounce) cans

    French's Fried Onions, divided

  • 1 1/2 pounds

    frozen green beans, thawed and drained



  1. Heat the oven to 325ºF. Arrange a rack in the middle of the oven and heat the oven to 325°F.

  2. Cook the mushrooms. Melt the butter in a large, straight-sided skillet over medium-high heat. Add the mushrooms and cook until reduced by half, about 5 minutes. Add the garlic and cook until fragrant, about 1 minute.

  3. Make the gravy. Sprinkle the flour evenly over the mushroom mixture and stir to combine. Cook until the flour is no longer dry, 1 to 2 minutes. Add the milk, chicken broth, tamari or soy sauce, pepper, and nutmeg and bring to a simmer. Simmer, stirring occasionally, until the sauce is thickened, 3 to 5 minutes.

  4. Add some of the fried onions and green beans. Remove the gravy from the heat. Add the green beans and half a can of the fried onions, and stir to combine. Transfer the green bean mixture to a 9x13-inch baking dish and spread into an even layer.

  5. Top and bake. Sprinkle with the remaining 1 1/2 cans onions. Bake until golden brown and bubbling, 12 to 15 minutes.

  6. Cool before serving. Let stand 10 minutes before serving. The sauce will thicken as it cools.

Recipe Notes

Make ahead: Assemble the casserole without the crisp onion topping and refrigerate tightly wrapped for up to 3 days. Remove from the refrigerator while the oven preheats. Top with the fried onions and bake.

Storage: Refrigerate leftovers tightly wrapped for up to 1 week.