Fish in mustard sauce is a delicious and flavorful dish that combines the delicate taste of fish with the tangy and spicy flavors of mustard. The fish is marinated in a mixture of mustard paste, lemon juice, and spices, then cooked in a creamy sauce made with mustard, yogurt, and spices. The result is a dish that is rich, creamy, and bursting with flavor. Serve this dish with steamed rice or naan for a satisfying meal.