There's no fixed recipe — vendors season each paper cup to order with a splash of vinegar and a pinch of salt, mint, or golpar, so no two cups taste quite the same.
Fava beans are boiled until soft, scooped into a paper cup straight off a warming pot, and finished to order with vinegar, salt, and a sprinkle of dried mint or golpar (angelica). Vendors sell it from carts around Rasht's Grand Bazaar as a cheap, warm snack for market-goers.