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Classic Green Bean Casserole (Upgraded Recipe) with Homemade Mushroom Sauce

Classic Green Bean Casserole (Upgraded Recipe)

Fresh green beans are folded into a homemade mushroom cream sauce and baked beneath a crisp layer of French-fried onions. This upgraded casserole serves 8 and may be assembled several hours ahead.
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Prep Time 25 minutes
Cook Time 35 minutes
Total Time 1 minute
Servings: 8 servings
Ingredients Method Notes

Ingredients
  

Green Beans and Sauce
  • 2 pounds Fresh green beans, trimmed
  • 3 tablespoons Unsalted butter
  • 8 ounces Cremini or white mushrooms, thinly sliced
  • 1 small onion or 2 Small yellow onion or shallots, finely chopped
  • 2 cloves Garlic cloves, minced
  • 1/4 cup All-purpose flour
  • 1 1/2 cups Chicken stock or vegetable stock
  • 1 cup Heavy cream or half-and-half
  • 1 teaspoon Kosher salt, plus more for blanching water
  • 1/2 teaspoon Freshly ground black pepper
  • 1/2 teaspoon fresh or 1/4 teaspoon dried Fresh thyme leaves or dried thyme
  • 1 teaspoon Soy sauce or Worcestershire sauce, optional
Topping
  • 1 1/2 to 2 cups French-fried onions
Optional Homemade Fried-Shallot Topping
  • 2 large Large shallots, very thinly sliced
  • 1/2 cup All-purpose flour
  • 1/2 teaspoon Kosher salt
  • As needed Neutral oil, such as canola or vegetable oil

Method
 

Step-by-Step
  1. Bring a large pot of well-salted water to a boil. Add the trimmed green beans and cook for 4–5 minutes, until bright green and just tender; transfer them immediately to ice water, then drain and dry thoroughly.
  2. Melt the butter in a large skillet over medium heat. Add the mushrooms and chopped onion, cooking for 7–10 minutes until the mushrooms release their moisture and begin to brown; stir in the garlic and thyme and cook for about 30 seconds.
  3. Stir the flour into the mushroom mixture and cook for 1 minute. Gradually whisk in the stock, followed by the cream, then simmer for 3–5 minutes until the sauce coats a spoon; season with salt, pepper, and optional soy sauce or Worcestershire sauce.
  4. Stir the blanched beans into the mushroom sauce. Transfer the mixture to a greased 9-by-13-inch baking dish, or cover and refrigerate it for several hours if preparing ahead.
  5. Bake the casserole uncovered at 375°F for 20–25 minutes, until hot and bubbling. Sprinkle the fried onions over the top during the final 5–10 minutes so they stay crisp; if using homemade fried shallots, add them near the end or immediately after baking.
  6. Let the casserole stand for 5 minutes before serving. This short rest allows the sauce to settle slightly while the topping remains crunchy.

Notes

Dry the blanched green beans thoroughly so the sauce does not become watery. For the crispest topping, refrigerate the assembled casserole separately from the fried onions and add them during the final minutes of baking.