The milk is left out overnight under the open sky, and the winter dew is said to be what lets it whip into such a light foam.
Sweetened milk froth flavoured with cardamom (often saffron) and topped with nuts, sold by Varanasi vendors on winter mornings.
Why it's made this way: This dew-set winter sweet (also called makhan malai) belongs to Uttar Pradesh cities such as Varanasi, Kanpur and Lucknow, and only appears in the cold months.