Quick Answer
To make green bean casserole from scratch, blanch 1 1/2 pounds of trimmed fresh green beans for 4 to 5 minutes, then cool them in ice water.
Cook mushrooms, onion and garlic in butter, stir in flour, then add broth and cream to make a thick sauce. Fold in the beans, top with crispy fried onions and bake at 350 F for about 25 minutes until bubbly.
For the classic shortcut, mix one 10.5 ounce can of cream of mushroom soup, 3/4 cup milk, 1 teaspoon soy sauce, 4 cups cooked beans and 1 1/3 cups fried onions, then bake.
Why Is Green Bean Casserole a Thanksgiving Classic?
The original recipe was developed in 1955 by Dorcas Reilly in the Campbell Soup Company test kitchen. It used pantry staples that most families had on hand, and it quickly became a holiday tradition.
It is still one of the most searched Thanksgiving recipes every fall. Google Trends lists it at the top of trending Thanksgiving recipes.
What Ingredients Do You Need?
For a from scratch casserole that serves 8:
- 1 1/2 pounds fresh green beans, trimmed and cut in 2 inch pieces
- 3 tablespoons butter
- 8 ounces cremini or white mushrooms, sliced
- 1 small onion, finely chopped
- 2 cloves garlic, minced
- 3 tablespoons all purpose flour
- 1 cup chicken or vegetable broth
- 1 cup heavy cream or half and half
- 1 teaspoon soy sauce
- 1/2 teaspoon salt and 1/4 teaspoon black pepper
- Pinch of nutmeg (optional)
- 1 1/2 cups crispy fried onions, divided
How Do You Make Green Bean Casserole, Step by Step?
1. Heat the oven. Preheat to 350 F and butter a 2 quart or 8 x 11 inch baking dish.
2. Blanch the beans. Boil the beans in salted water for 4 to 5 minutes, until bright green and crisp tender. Drain and plunge into ice water, then drain well.
3. Cook the mushrooms. Melt the butter in a large skillet over medium high heat. Cook the mushrooms for 6 to 8 minutes, until browned and their liquid evaporates.
4. Add aromatics. Stir in the onion and cook 3 minutes, then the garlic for 30 seconds.
5. Make the sauce. Sprinkle in the flour and stir for 1 minute. Slowly whisk in the broth, then the cream. Simmer 3 to 5 minutes until thick. Season with soy sauce, salt, pepper and nutmeg.
6. Combine. Fold the beans and 1/2 cup of the fried onions into the sauce. Spread in the baking dish.
7. Bake. Bake for 20 minutes, until bubbling at the edges.
8. Top and finish. Scatter the remaining onions on top and bake 5 more minutes, until golden.
Fresh, Frozen or Canned Green Beans?
- Fresh: best texture and color. Blanch first so they stay bright and tender.
- Frozen: very good and convenient. Thaw and pat dry, no blanching needed.
- Canned: softest texture, the classic choice for the shortcut recipe. Drain very well.
How Do You Make the Classic Shortcut Version?
1. Mix. Stir together one 10.5 ounce can of condensed cream of mushroom soup, 3/4 cup milk, 1 teaspoon soy sauce and 1/8 teaspoon black pepper in a 1 1/2 quart dish.
2. Add beans. Stir in 4 cups of cooked cut green beans and 2/3 cup fried onions.
3. Bake. Bake at 350 F for 25 minutes. Stir, top with another 2/3 cup onions and bake 5 minutes more.
How Do You Keep It From Being Soggy?
- Do not overcook the beans before baking. Crisp tender is the goal.
- Dry the beans well after blanching or thawing, since extra water thins the sauce.
- Cook the mushrooms until their liquid is gone.
- Add most of the fried onions at the end so they stay crunchy.
Can You Make It Ahead?
Yes. Assemble the casserole without the onion topping up to 2 days ahead, cover and refrigerate.
On the day, let it sit out for 30 minutes, then bake 30 to 35 minutes since it starts cold. Add the topping for the last 5 minutes. This frees up oven space on Thanksgiving.
What Variations Can You Try?
- Cheesy: stir 1 cup shredded Gruyere or cheddar into the sauce.
- Bacon: cook 4 slices, crumble, and fold in. Use some fat to cook the mushrooms.
- Homemade onions: toss thin shallot slices in flour and fry until crisp.
- Lighter: use milk instead of cream and top with toasted panko and almonds.
- Vegetarian: use vegetable broth. The recipe is otherwise meat free.
- Gluten free: thicken with cornstarch and use gluten free fried onions and tamari.
How Do You Store Leftovers?
Refrigerate leftovers within 2 hours in a covered container. USDA FSIS advises using leftovers within 3 to 4 days and reheating them to 165 F.
Reheat in the oven at 350 F, covered, for 15 to 20 minutes, then uncover for a few minutes to re crisp the top. The microwave works but softens the onions.
Green bean casserole does not freeze especially well, because the cream sauce can separate and the beans soften.
What Goes Well With Green Bean Casserole?
It pairs with roast turkey, ham, mashed potatoes, stuffing and cranberry sauce. Its creamy, savory flavor balances sweet sides like candied yams and sweet potato casserole.
How Do You Scale Green Bean Casserole for a Crowd?
Double the recipe and bake it in a 9 x 13 inch dish for about 16 servings. Add 5 to 10 minutes to the baking time, since the deeper dish takes longer to heat through.
A good rule is about 1/2 cup of casserole per person when there are several other sides on the table.
Frequently Asked Questions
How long do I bake green bean casserole?
About 25 to 30 minutes at 350 F, until bubbling.
Can I make it without canned soup?
Yes. The from scratch mushroom cream sauce above replaces it.
Can I use a slow cooker?
Yes. Cook on low for 3 to 4 hours, then add onions just before serving.
How many does it serve?
This recipe serves about 8 as a side.
The Bottom Line
Green bean casserole is easy: crisp tender beans, a creamy mushroom sauce and a crunchy onion topping, baked at 350 F until bubbling.
Make it from scratch for the best flavor, or use the classic canned soup shortcut. Assemble ahead and add the onions at the end for the crispiest top.
