Braised Striped Bass

Original recipe. We have used wild striped bass almost always for this dish. Serves 6ppl. For the broth: 3 tablespoons extra-virgin olive oil  1/2 yellow onion, peeled and sliced  1 small carrot, peeled and sliced  1/2 fennel bulb, cored and sliced  1 celery stalk, sliced  1 shallot, peeled and sliced  Kosher salt and freshly ground black pepper  1 teaspoon coriander seeds, toasted  1 teaspoon fennel seeds, toasted  1 cup dry white wine  1 cup white wine vinegar  1 quart fumet  3 sprigs fresh thyme  1 bay leaf  3 sprigs fresh tarragon  1 sprig fresh rosemary  For the bass: 4 tablespoons extra-virgin olive oil  Kosher salt and freshly ground black pepper  6 6-ounce, skin-on striped bass fillets (about 1 1/4 inches thick)  3 sprigs fresh thyme, plus additional for garnish if desired  PREPARATION: For the broth: Heat the olive oil in a large pot over medium heat.  Add the onion, carrot, fennel, celery, and shallot and season with salt and pepper. Sweat the vegetables until they are soft, about 20 minutes. Add the coriander and fennel seeds, wine, and vinegar and simmer until reduced by half, about 10 minutes. Add the fumet, 1 cup water, the thyme, bay leaf, tarragon, and rosemary. Simmer until the flavors in the broth blend, about 15 minutes; set aside to cool.  For the bass: Divide the oil between two large skillets and heat over medium. Salt and pepper the fish and add it, skin side down, to the skillet. Add the thyme and cook until the skin is crisp, about 6 minutes. Turn the fish, then ladle two cups of the broth with vegetables into each skillet, reserving the remainder. Bring the broth to a simmer, then reduce the heat to medium-low and gently simmer the bass until it is opaque throughout, about 5 minutes more.  To serve: Bring the reserved broth to a simmer, then ladle it into warm shallow bowls. Place a piece of fish in each bowl, garnish with fresh thyme, if desired, and serve.