Classic Green Bean Casserole From Scratch

Classic Green Bean Casserole From Scratch


  • 1 pound fresh green beans, trimmed
  • 2 tablespoons olive oil
  • Salt and pepper to taste
  • 8 ounces white button mushrooms, sliced
  • 3 tablespoons unsalted butter
  • 1/4 cup all-purpose flour
  • 2 cups whole milk
  • 1/2 teaspoon garlic powder
  • 1/4 teaspoon onion powder
  • 1/8 teaspoon ground nutmeg
  • 1/2 teaspoon salt
  • Freshly ground black pepper to taste
  • 1 (10.5 ounce) can condensed cream of mushroom soup
  • 1 cup sour cream
  • 1 (4.5 ounce) can fried French-fried onions


  • Preheat your oven to 375°F (190°C). Grease a 2-quart baking dish with nonstick cooking spray and set it aside.
  • Bring a large pot of salted water to a boil over high heat. Add the green beans and cook for about 4 minutes or until they are crisp-tender. Drain them in a colander and rinse under cold water to stop the cooking process. Set aside.
  • Heat the olive oil in a large skillet over medium heat. Add the sliced mushrooms and sauté for about 5 minutes or until they are browned and tender. Remove from the heat and set aside.
  • Melt the butter in the same skillet over medium heat. Whisk in the flour until it forms a smooth paste (roux). Cook for about 1 minute, stirring constantly.
  • Gradually whisk in the whole milk. Bring the mixture to a simmer and cook for about 3 minutes or until it thickens slightly. Stir in the garlic powder, onion powder, nutmeg, salt, and black pepper. Whisk in the condensed cream of mushroom soup and sour cream until smooth.
  • Stir in the cooked green beans and sautéed mushrooms. Pour the mixture into the prepared baking dish. Top with the fried French-fried onions.
  • Bake for about 25 minutes or until the casserole is bubbly and the onions are golden brown. Remove from the oven and let it cool for about 10 minutes before serving.