Seared Cod in Cherry Tomato and Tarragon Nage

Made with white wine, vegetables and aromatic herbs, nage-a French-style broth-preserves the delicate texture and moisture of the fish. In this recipe, almost any fish is suitable, but the taste of the broth is especially well complemented by tender fish with white flesh.
Season the fish with salt and pepper. Melt the butter in a large skillet over medium-high heat. Cook the fish until it is lightly browned on the bottom, about 3 minutes. Transfer the fish to a plate with the browned side facing up.Add the carrots to the pan along with the broth, wine, vinegar, peppercorns, bay leaf and tarragon sprigs and bring to a boil. Reduce the heat and simmer until the carrots are tender, 8 to 9 minutes.Meanwhile, combine the lemon zest and crushed tarragon and spread on the browned part of the fish. Place the fish, browned side up, with the remaining juice in the pan. Add the tomatoes and simmer until the fish is cooked through, 2 to 6 minutes, depending on its thickness.Remove and discard the bay leaf and tarragon sprigs. Divide the fish into 4 wide, shallow plates, then arrange the vegetables and slice into plates. Drizzle each bowl with 1/2 tsp lemon juice and 1 tsp oil.