Ingredients

Béchamel Sauce (warmed)

1 1/2 pounds fresh green beans, ends trimmed, cut into 2-inch pieces (about 4 cups)

1/4 cup olive oil

1/2 pound fresh cremini mushrooms, thinly sliced (about 2 cups)

2 cloves garlic, minced

2 teaspoons minced thyme leaves

5 medium shallots, sliced (about 1 1/3 cups)

3/4 cup flour for dusting shallots

2 cups vegetable oil for frying

Preparation

  1. Heat oven to 400°F. Bring a large pot of salted water to a boil. Add green beans and cook until bright green and just tender, about 6 minutes; drain in a colander and rinse under cold water until cold. Set aside.
  2. Heat olive oil in a large frying pan over medium-high heat. When oil is hot and shimmering, add mushrooms and season with salt and freshly ground black pepper. Sauté, stirring occasionally, until mushrooms are brown on edges, about 4 minutes. Add garlic and cook 1 minute more.
  3. Combine green beans, mushroom mixture, béchamel sauce, and thyme in a large bowl and mix thoroughly. Taste and adjust seasoning if necessary. Transfer into a 2-1/2-quart baking dish and set aside.
  4. Dust sliced shallots in flour and shake off excess. Set aside.
  5. Pour vegetable oil into a large 10-inch frying pan (should be 1 inch deep). Heat over medium-high heat to 350°F, about 4 minutes.
  6. Fry shallots in batches, until light golden brown on edges, about 2 minutes. Remove to a paper-towel-lined plate and season with salt and freshly ground black pepper.
  7. Top casserole with fried shallots and bake in oven until shallots are golden and crispy and casserole is bubbly and heated through, about 12 to 15 minutes.