Description
A classic Green Bean Casserole made with tender blanched green beans, a rich mushroom sauce infused with garlic and thyme, topped with crispy French fried onions and Parmesan cheese for a delightful holiday side dish.
Ingredients
Scale
Vegetables
- 1½ pounds green beans, trimmed and halved
- 16 ounces cremini mushrooms, sliced
- 4 garlic cloves, minced
- 2 tablespoons fresh thyme leaves
Sauce
- 2 tablespoons extra-virgin olive oil
- 2 tablespoons tamari
- ¼ cup all-purpose flour
- 3 cups milk, any kind
- 1½ teaspoons Dijon mustard
- ½ cup grated Parmesan cheese, plus more for sprinkling
- ¼ teaspoon freshly ground black pepper
Topping
- 1½ cups French fried onions, or homemade Crispy Baked Onions (see recipe notes)
Instructions
- Preheat Oven and Prepare Baking Dish: Preheat the oven to 400°F. Lightly grease a 9×13-inch baking dish to prevent sticking.
- Blanch Green Beans: Bring a large pot of salted water to a boil. Have a large bowl with ice water ready. Add the green beans to the boiling water and cook for 4 minutes. Drain immediately and immerse the green beans in the ice water to halt the cooking. Drain again and pat dry on a towel.
- Cook Mushroom Sauce: Heat the olive oil in a large skillet over medium heat. Add the sliced mushrooms and cook until soft, about 8 to 10 minutes. Stir in tamari, minced garlic, and fresh thyme leaves. Sprinkle flour over the mushrooms and stir well to combine. Gradually pour in the milk and add Dijon mustard while stirring. Let the sauce simmer and thicken for 15 to 20 minutes, whisking often to avoid lumps. Stir in the grated Parmesan cheese and freshly ground black pepper.
- Assemble Casserole: Spread one-third of the mushroom sauce evenly in the prepared baking dish. Layer the blanched green beans over the sauce, then top with the remaining mushroom sauce. Sprinkle the French fried onions evenly on top.
- Bake Casserole: Cover the dish with foil and bake in the preheated oven for 10 minutes. Remove the foil and bake uncovered for an additional 10 minutes. If the onions begin to brown too rapidly, cover the dish again for the rest of the baking time.
- Garnish and Serve: Optionally, sprinkle extra Parmesan cheese on top before serving. Serve the casserole hot as a delicious side dish.
Notes
- To make homemade crispy baked onions: Preheat oven to 450°F and line two large baking sheets with parchment paper. Thinly slice 2 medium yellow onions and toss them with 4 teaspoons olive oil, ½ cup all-purpose flour, 2 tablespoons panko bread crumbs, and ½ teaspoon sea salt in a bowl. Spread evenly on baking sheets and bake for 25 to 35 minutes, tossing every 10 minutes and rotating pans as needed until golden and crispy. Store at room temperature until needed.
- For a vegan version, omit the Parmesan cheese and add extra salt to the mushroom sauce to compensate for flavor.
- Be careful not to overcook the green beans during blanching to maintain a slight crispness and vibrant color.
- If French fried onions brown too quickly during baking, covering the casserole will prevent burning.
Nutrition
- Serving Size: 1 cup
- Calories: 220 kcal
- Sugar: 4 g
- Sodium: 350 mg
- Fat: 12 g
- Saturated Fat: 4 g
- Unsaturated Fat: 7 g
- Trans Fat: 0 g
- Carbohydrates: 18 g
- Fiber: 4 g
- Protein: 8 g
- Cholesterol: 15 mg
