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Green bean casserole on a plate with a fork.

Green Bean Casserole

For the best Green Bean Casserole, make a simple homemade mushroom cream sauce and a crunchy topping with both fried onions and bread crumbs.
Course Side Dish
Cuisine American
Prep Time 10 minutes
Cook Time 45 minutes
Total Time 55 minutes
Servings 12 servings
Calories 295kcal


For the topping:

  • 4 slices white sandwich bread torn into quarters
  • 2 tablespoons butter softened
  • Salt and freshly ground black pepper
  • 3 cups canned fried onions (about 6 ounces)

For the casserole:

  • Salt and freshly ground black pepper
  • 2 pounds green beans ends trimmed, halved (see note 1)
  • 3 tablespoons butter
  • 1 pound white button mushrooms wiped clean and sliced (see note 2)
  • 3 cloves garlic minced
  • 3 tablespoons all-purpose flour
  • 1 1/2 cups chicken broth
  • 1 1/2 cups heavy cream


To make the topping:

  • In a food processor or blender, pulse bread, butter, 1/4 teaspoon salt, and 1/8 teaspoon pepper until coarse crumbs form (about 10 pulses). Transfer to a large bowl. Add onions and toss to combine.

To make the casserole:

  • Adjust an oven rack to middle position and preheat oven to 425 degrees. In a Dutch oven or stock pot, bring 4 quarts water and 2 tablespoons salt to boil. Fill a large bowl with ice water.
  • Add green beans and cook until bright green and tender-crisp, about 6 minutes. Drain in colander and immediately transfer to ice water. Spread on paper towels to dry.
  • To the same pot, melt the butter over medium-high heat until foaming. Add mushrooms, garlic, 3/4 teaspoon salt, and 1/8 teaspoon pepper. Cook until the mushrooms have released most of their liquid, about 5 minutes.
  •  Stir in flour and cook for one minute. Whisk in broth, scraping up any brown bits from the bottom of the pan. Bring to a boil, whisking constantly.
  • Reduce heat to medium. Whisk in cream and simmer until the sauce has thickened and reduced to 3 1/2 cups, about 10 to 15 minutes. Season to taste with salt and pepper.
  • Add the green beans to the pot with the mushroom sauce and toss until evenly coated. Pour into a 3-quart or 9-inch by 13-inch baking dish. Sprinkle with topping.
  • Bake until the top is golden brown and the sauce is bubbling around the edges, about 15 minutes. Serve immediately.



  1. Green beans: To substitute frozen green beans, microwave 2 (12-ounce) bags of frozen cut green beans according to the package instructions (or microwave on HIGH power for 4 to 5 minutes; let stand 1 minute before removing from the microwave). Drain well (I like to use a salad spinner to spin them dry).
  2. Mushrooms: Use fresh mushrooms to make a quick from-scratch cream of mushroom sauce.
  3. Yield: This recipe makes enough for 10 as a side dish (or more depending on how many sides you have at Thanksgiving).
  4. Storage: Store leftovers covered in the refrigerator for up to 4 days.
  5. Make the topping ahead: The bread crumb topping can be prepared ahead of time and stored in an air-tight container in the refrigerator. Combine with fried onions just before baking.
  6. Make the beans and sauce ahead: The beans may be blanched in advance, cooled, and stirred into the cooled mushroom sauce. Transfer to the baking dish, cover, and refrigerate up to 24 hours in advance. Heat the casserole for 10 minutes in a 425-degree oven before adding the topping, then bake as directed. 
  7. Half batch: Prepare in a 2-quart or 8-inch square baking dish. Reduce the sauce cooking time to about 6 minutes for 1 3/4 cups. Reduce the baking time to 10 minutes in Step 4.
  8. Small batch: Green bean casserole for two is made with 8 ounces frozen green beans.
  9. Slow cooker green bean casserole: Follow the recipe through Step 6, but instead of using a baking dish, transfer the mixture to a slow cooker. Cover and cook on HIGH for 2 to 3 hours or LOW for 4 to 6 hours. Omit the bread crumbs and top with 3 cups fried onions immediately before serving.


Calories: 295kcal | Carbohydrates: 19g | Protein: 4g | Fat: 23g | Saturated Fat: 13g | Trans Fat: 1g | Cholesterol: 53mg | Sodium: 325mg | Potassium: 342mg | Fiber: 3g | Sugar: 4g | Vitamin A: 1105IU | Vitamin C: 12mg | Calcium: 75mg | Iron: 1mg