Ingredients
1/4 cup olive oil
4 tablespoons unsalted butter
4 large leeks (about 10 cups), white and light-green parts only, cut into thin matchsticks, well washed, and dried
4 shallots (1 cup), thinly sliced into rings
8 medium garlic cloves, thinly sliced
Coarse salt and freshly ground pepper
10 (each 6 ounces, 1 inch thick; preferably square cuts) halibut fillets, skinned
2 pounds oyster mushrooms, halved if large
Chive Oil, for drizzling
Red and Golden Beet Salad, for serving
Preparation
Preheat oven to 400 degrees. Heat 2 tablespoons oil and the butter in a large skillet over medium heat. Add leeks, shallots, garlic, and 1/8 teaspoon each salt and pepper. Cook, stirring, until leeks and shallots are translucent, about 3 minutes. Spread into two 9-by-13-inch baking dishes, dividing evenly. Top with fish; season with salt and pepper. Set aside.
Heat 1 tablespoon oil in same skillet over medium heat. Add half of the mushrooms and 1/2 teaspoon salt. Raise heat to medium-high; cook, stirring, until tender, 3 to 5 minutes. Scatter mushrooms over fish. Repeat with remaining oil and mushrooms and 1/2 teaspoon salt.
Bake until fish is cooked through, 18 to 20 minutes. Transfer to plates. Drizzle with chive oil. Serve with beet salad.
