Onion curry is a versatile Indian dish featuring onions as the star, often balancing sweetness and tanginess with spices like turmeric, coriander, and chili, and can range from a simple, quick side with rice or roti (chapati) to richer, creamier gravies with coconut, yogurt, or nuts, sometimes incorporating other proteins like chicken or paneer, with regional variations like Kerala's spicy Ulli Curry or North Indian Dopiaza (double onion).