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5.0 from 15 votes

Easy Green Bean Casserole

Looking for a tasty Green Bean Casserole recipe that's perfect for Thanksgiving or the holidays? This one's a winner. It's loaded with fresh green beans and mushrooms, all in a creamy béchamel sauce and topped with crispy fried onions. It's bursting with flavor and incredibly comforting.

Prep Time
15 mins
Cook Time
15 mins
Total Time
1 hr
Servings: 9
Calories: 291 kcal
Course: Side Dish , Main Course
Cuisine: American

Ingredients

For the Green Beans:
  • 2 pounds fresh green beans , trim the ends
  • 1 pound crimini , baby Bella or portabella mushrooms, sliced
  • 4 tablespoons extra virgin olive oil
  • ½ teaspoon kosher salt
  • ½ teaspoon freshly ground black pepper
For the Bechamel Sauce:
  • 1 medium sweet or yellow onion , chopped
  • 4 garlic , minced
  • 1 oz (1-½ cups) evaporated milk or whole milk
  • ½ cup whole milk
  • 5 tablespooons unsalted butter
  • ¼ cup all-purpose flour
  • ½ teaspoon freshly grated nutmeg
  • ¼ teaspoon ground black pepper
  • 1 teaspoon kosher salt , to taste
  • ½ cup freshly grated Grana Padano or Parmesan cheese
For the Topping:
  • 6 oz (170g) cup French’s fried onions

Instructions

    Cup of Yum
  1. Preheat the Oven: Preheat your oven to 450°F (230°C).
  2. Roast the Vegetables: In a large bowl, mix together the green beans and sliced mushrooms. Season with salt and pepper. Drizzle the olive oil over the vegetables and toss to coat evenly. Spread the vegetables on two rimmed baking sheets in a single layer. Roast for 20-25 minutes, stirring occasionally, until the mushrooms are browned, the green beans are tender, and any liquid has evaporated. Remove the vegetables from the oven. Reduce the oven temperature to 400°F (200°C).
  3. Prepare the Bechamel Sauce: In a medium saucepan, melt the butter over medium heat. Add the onions, cooking until soft, about 8-10 minutes. Stir in the minced garlic and cook for another minute until fragrant. Whisk in the flour to form a smooth mixture. Cook for 3 minutes. Gradually add both the evaporated and regular milk, whisking constantly to avoid lumps. Continue to simmer, stirring constantly, until the sauce thickens, about 10 minutes. Remove from heat and stir in the cheese, salt, pepper, and a pinch of nutmeg. Adjust the consistency with more milk if needed.
  4. Assemble and Bake the Casserole: Fold the roasted vegetables into the bechamel sauce. Transfer the mixture to a buttered 4-quart baking dish. Bake in the preheated oven for 15 minutes until warmed through.
  5. Finish with Toppings: Remove the casserole from the oven and top it with the crispy fried onions. Return it to the oven for an additional 3-5 minutes until the onions are slightly golden and fragrant.
  6. Serve: Let the casserole rest for a few minutes before serving.
  7. Top the Green Bean Casserole with fried onions and bake until onions are slightly darker and fragrant about 5 minutes. Remove the Green Bean Casserole from the oven and let it sit for 10 minutes to set before serving.

Notes

  • How to Store & Re-Heat
  • Store Green Bean Casserole in an airtight container in the refrigerator for up to 3 days. Reheat in a preheated 350F oven for 30 to 35 minutes until heated through or in the microwave until you achieve your desired temperature.
  • Make Ahead & Freeze
  • Green Bean Casserole (without crispy onions) can be made a day ahead. Cool, wrap, and refrigerate for 3 days. To freeze, cool, wrap, label, and freeze for 2 weeks. Reheat at 350°F, covered, for 25-30 mins, then top with onions and bake 3-5 mins more.