Rasiao (also rasiav or rasiaav) is the jaggery rice-pudding eaten on Kharna, the second day of Chhath, the most important festival of Mithila. Unlike an everyday kheer sweetened with sugar, rasiao takes its dark colour and deep, mineral sweetness from gur (jaggery), simmered with rice and milk. It is cooked in ritual purity — vegetarian, without salt, onion or garlic — and the vrati (the faster) breaks the day’s fast with it after sunset, sharing the household’s first prasad of the festival.
The method is unhurried: rice is boiled soft in milk, jaggery is melted separately so the milk does not curdle and then folded in, and the kheer is finished with a little ghee. It is eaten with a plain wheat roti cooked on a clay chulha. With the Kharna meal complete, the vrati begins the formidable ~36-hour waterless fast that culminates in the arghya to the setting and rising sun — making rasiao the threshold dish that opens Chhath proper.
