Cod Baked in Foil with Fennel and Shallots

Name: Cod Baked in Foil with Fennel and Shallots
Ingredients: 1 large fennel bulb (about 1 pound), trimmed, halved, cored, and sliced into 1/4-inch strips (about 4 cups); 2 medium shallots , sliced thin (about 1/2 cup); 4 tablespoons unsalted butter , softened; 2 medium oranges , 1/4 teaspoon finely grated zest removed from one; both peeled, quartered, and cut crosswise into 1/4-inch-thick pieces (see note); 1 medium garlic clove , minced or pressed through garlic press (about 1 teaspoon); 2 teaspoons minced fresh tarragon leaves; Salt and ground black pepper; 4 tablespoons vermouth or dry white wine; 4 skinless cod fillets , 1 to 1 1/4 inches thick (about 6 ounces each)