Ingredients
Equipment
Method
- Preheat your oven to 350°F (175°C). Prepare an ice bath in a large bowl. In a large pot, bring generously salted water to a boil. Cook the green beans until bright green, about 2 to 3 minutes. Transfer the beans to the ice bath to cool. Drain the beans and set them aside in another large bowl.
- In another large pot or saucepan over medium heat, melt 4 tablespoons of butter. Add the sliced onions and a large pinch of salt. Cook, stirring occasionally, until the onions begin to soften, about 7 minutes. Add the mushrooms and cook, stirring often, until they are browned, about 7 more minutes. Stir in the garlic and cook until fragrant, about 1 minute. Season with salt and pepper. Transfer this onion and mushroom mixture to the bowl with the green beans.
- In the same pot over medium heat, melt the remaining 8 tablespoons of butter. Add the flour and cook, whisking frequently, until it turns golden and smells toasty, about 3 minutes. Gradually whisk in the milk. Season with salt and pepper. Bring the mixture to a simmer and cook, stirring occasionally, until it thickens, about 4 minutes. Pour this sauce into the bowl with the green beans and stir to combine everything. Transfer the mixture to a 13" x 9" baking dish.
- Bake the green bean casserole until it is warmed through and bubbling, about 30 minutes.
- Top the casserole with the fried onions. Continue to bake until the onions are warmed through, about 5 minutes more.
Nutrition
Notes
This recipe can be prepared ahead of time. You can blanch the green beans and make the sauce separately. Assemble and bake just before serving. For a richer flavor, consider using a mix of butter and olive oil when sautéing the onions and mushrooms.