Green Bean Casserole From Scratch (No Canned Soup)

Green bean casserole is the side dish that shows up at nearly every Thanksgiving table in America, and for good reason: tender green beans folded into a creamy, savory sauce and finished with a crunchy onion topping is pure comfort. This green bean casserole from scratch keeps everything that makes the classic great and rebuilds it without a single can — fresh green beans instead of canned, a homemade mushroom cream sauce instead of condensed soup, and crispy fried onions made in your own skillet instead of from a bag. The result tastes like the casserole you grew up with, just brighter, fresher, and more deeply savory.

Making it from scratch is simpler than it sounds because the three parts come together in a natural order. While the beans blanch, the onions fry up golden; while those drain, the mushrooms cook down into a velvety cream sauce that coats every bean. Nothing here requires special equipment or tricky technique — just a big pot, a skillet, and a 9×13 baking dish. The whole thing takes a little over an hour, most of it hands-off oven time, and it serves 8 to 10 as a holiday side.

What you gain over the canned-soup version is control and flavor. Fresh beans stay vivid green and pleasantly crisp-tender instead of soft and gray. Real mushrooms — browned until their edges caramelize — give the sauce a deep, earthy richness that condensed soup cannot match. And homemade crispy onions, fried until shattering and salted while hot, add a crunch that stays crunchy. This is the green bean casserole that converts the skeptics and makes the rest of the table ask for the recipe.

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Ingredients

For the crispy fried onions:

• 2 large yellow onions, sliced paper-thin (about 4 cups / 400 g)
• 1 cup (240 ml) buttermilk (or 1 cup milk mixed with 1 tablespoon vinegar, rested 5 minutes)
• 1 cup (125 g) all-purpose flour
• 1 teaspoon (6 g) kosher salt, plus more for sprinkling
• 1/2 teaspoon (2 g) freshly ground black pepper
• Vegetable oil, for frying (about 2 cups / 480 ml, for 1/2-inch depth)

For the mushroom cream sauce:

• 8 ounces (225 g) cremini mushrooms, sliced
• 4 tablespoons (55 g) unsalted butter
• 1 small yellow onion, finely diced (about 1 cup / 150 g)
• 3 cloves garlic, minced
• 1/4 cup (30 g) all-purpose flour
• 1 cup (240 ml) chicken or vegetable broth
• 1 cup (240 ml) heavy cream (or half-and-half)
• 1 teaspoon (5 ml) Worcestershire sauce or soy sauce
• 1 teaspoon (6 g) kosher salt
• 1/2 teaspoon (2 g) freshly ground black pepper
• 1/4 teaspoon ground nutmeg (optional)

For the casserole:

• 1 1/2 pounds (680 g) fresh green beans, trimmed and cut in half
• Butter or oil, for greasing the baking dish

Instructions

1. Soak and dredge the onions. Place the sliced onions in a bowl, pour the buttermilk over them, and let them soak for 15 minutes. In a shallow dish, whisk the flour with 1 teaspoon salt and the pepper. Lift the onions out of the buttermilk a handful at a time, letting the excess drip off, and toss them in the seasoned flour until lightly coated.
2. Fry the crispy onions. Pour oil into a large heavy skillet to a depth of 1/2 inch and heat over medium-high heat to 350°F (175°C). Working in batches, fry the coated onions for 3–4 minutes, stirring gently, until deep golden brown and crisp. Lift them out with a slotted spoon, drain on a wire rack set over a baking sheet, and sprinkle with salt while hot. Repeat with the remaining onions.
3. Blanch the green beans. Bring a large pot of salted water to a rolling boil. Add the green beans and cook for 4–5 minutes, until bright green and crisp-tender. Drain and immediately plunge them into a bowl of ice water to stop the cooking, then drain well and pat dry.
4. Brown the mushrooms. In a large skillet over medium-high heat, melt the butter. Add the sliced mushrooms in a single layer and cook undisturbed for 3–4 minutes, until browned on one side. Stir and continue cooking for 3–4 minutes more, until golden all over.
5. Build the sauce. Add the diced onion to the mushrooms and cook for 4–5 minutes, until soft. Stir in the garlic and cook 1 minute more. Sprinkle the flour over the vegetables and stir for 1–2 minutes to cook out the raw flour taste.

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6. Add the liquids. Slowly pour in the broth, stirring constantly to avoid lumps. Stir in the cream, Worcestershire sauce, salt, pepper, and nutmeg if using. Bring to a gentle simmer and cook for 3–4 minutes, stirring, until the sauce thickens enough to coat the back of a spoon. Taste and adjust the salt.
7. Assemble the casserole. Preheat the oven to 375°F (190°C). Grease a 9×13-inch (3-quart) baking dish. Add the blanched green beans to the skillet with the sauce (or combine in a large bowl) and fold gently until every bean is coated. Transfer to the baking dish and spread evenly.

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8. Bake. Bake for 20–25 minutes, until the sauce is bubbling around the edges.
9. Top and finish. Remove the dish from the oven and scatter the crispy fried onions evenly over the top. Return to the oven for 5–8 minutes more, until the topping is deeply golden and the sauce bubbles through.
10. Rest and serve. Let the casserole rest for 10 minutes so the sauce sets, then serve warm.

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Variations

• Cheesy green bean casserole: stir 1 cup shredded sharp cheddar or Gruyère into the hot sauce until melted before adding the beans.
• Bacon and onion: fold 6 slices of cooked, crumbled bacon into the bean mixture before baking for a smoky note.
• Parmesan panko topper: replace half the fried onions with buttered panko tossed with 1/2 cup grated Parmesan for a cheesier crunch.
• Mushroom-forward: double the mushrooms to a full pound and skip half the onions for an earthier, more savory casserole.
• Dairy-free version: use olive oil instead of butter, a rich vegetable broth, and full-fat coconut milk in place of the cream; the sauce still thickens and browns beautifully.
• Spicy kick: add 1/2 teaspoon smoked paprika and a pinch of cayenne to the flour dredge for the crispy onions.

Storage and Reheating

Leftover green bean casserole keeps in the refrigerator for up to 4 days. Cool it completely, then cover the baking dish tightly with foil or transfer portions to airtight containers. The crispy onion topping will soften in the fridge — that is normal, and a hot oven brings much of the crunch back. For longer storage, freeze the unbaked or baked casserole (without the onion topping) in a freezer-safe container for up to 2 months; thaw overnight in the refrigerator before reheating.

Reheat covered at 350°F (175°C) for 20–25 minutes, until heated through. For the best texture, add a fresh handful of crispy fried onions on top for the last 5 minutes of reheating so the topping is crunchy. Single servings reheat well in the microwave in 1–2 minute bursts, though the topping will stay soft that way. Do not refreeze leftovers that have already been thawed.

Make-Ahead

This casserole is built for a busy holiday schedule. Blanch the green beans and make the mushroom cream sauce up to 2 days ahead; store them separately in the refrigerator (keep the sauce in an airtight container). Fry the crispy onions up to 1 day ahead and keep them in an airtight container at room temperature — do not refrigerate them or they will soften. On baking day, fold the cold beans and sauce together in the baking dish, add 5–10 minutes to the covered bake since everything starts cold, and top with the crispy onions for the final few minutes as directed.

You can also fully assemble the unbaked casserole (beans plus sauce, no onion topping) in the baking dish, cover tightly, and refrigerate for up to 24 hours. Bake straight from the fridge, adding about 10 extra minutes to the first bake before the topping goes on. Never top it with the onions before refrigerating — add them fresh at the end so they stay crisp.

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Emma Carter

Hi, I’m Emma! I’m the cook and recipe developer behind Sizzle & Sage. From my sunny home kitchen, I share easy, flavor-packed recipes for real life — quick breakfasts, cozy weeknight dinners, and simple bakes anyone can make. Pull up a chair and stay a while!