Earlier this month, entrepreneurs Victoria and Grace Sheppard finally opened their London coffee shop, Queens of Mayfair.The sisters' new venture serves high-end coffee, fresh pastries, charcuterie boards and cocktails.We want to be the middle ground between the pubs and five star hotels in Mayfair for local workers to catch up on lost socializing, Victoria Sheppard.Less than two weeks after their first day, the Sheppards have already secured a partnership with Difference Coffee.This ultra-premium roaster provides beans to over a dozen Michelin-starred restaurants.And their coffee shop is the only place to get the beans outside of an exclusive sit-down restaurant.And that is part of the reason they are selling the most expensive cup of coffee in the country, for £50 ($64) per serving.If that's a little too rich for your tastes, Queens does have other, more reasonably priced coffees