Black cod--also known as butterfish or sablefish--has a buttery-sweet flavor and tender texture, making it the perfect foil to this citrus and soy glaze that is loosely based on the Japanese condiment called ponzu sauce. Lemon and lime play starring roles in June's take on ponzu sauce, giving it a tart and tangy flavor that is similar to a vinaigrette, while sugar and mirin balance out the flavors for a sophisticated finish. Serve your glazed black cod with rice and steamed vegetables for an elegant dinner.