Ingredients 2 dried bay leaves 3 to 5 sprigs flat-leaf parsley 3 to 5 sprigs thyme 3 to 5 sprigs tarragon 3 to 5 sprigs dill 1 tablespoon fennel seeds 1 tablespoon whole black peppercorns 4 tablespoons unsalted butter 2 large leeks, white and pale-green parts, quartered lengthwise and sliced 1/2 inch thick, washed well 1 large Spanish onion, cut into 1-inch pieces 1 pound white mushrooms, quartered 2 carrots, cut into 1-inch pieces 2 celery stalks, cut into 1-inch pieces 1 fennel bulb, trimmed and cut into 1-inch pieces 7 pounds heads and bones of non-oily fish, such as sole, flounder, or bass 3 cups dry white wine Preparation Make a bouquet garni by tying bay leaves, parsley, thyme, tarragon, dill, fennel seeds, and peppercorns in a piece of cheesecloth; set aside....