To make simple syrup, combine equal parts white sugar and water in a pot, bring to a boil, then let simmer for five minutes. Bring to room temperature and use as needed.
Pour vodka, lime juice and simple syrup into a glass. Fill with ice and top up with ginger beer. (Bonus points if you have a proper, copper Moscow Mule cup!)
While Moscow isn't exactly the beacon of Summer, this crisp cocktail is just in season. A combination of vodka, lime juice and ginger beer gives it a spicy taste, with a clean, citrus-based finish.