Honestly, I'm too far removed from the culture in Iran to nail the second part, but I'm a big fan of the drinks at Cafe Aunja in Montreal, and Komaaj in San Francisco is wonderful too.

Sour cherry sharbat is very easy to do at home, too. You just need a bottle of sour cherry syrup (sadaf, golchin, and marco polo are all solid brands in the US). Pour a tablespoon or two into an empty glass, add water or seltzer on top, add ice, mix it all up with a spoon, and you're good to go.