Put the lime juice, simple syrup and the mint sprig into your shaker and muddle (using your cocktail muddler). Add the gin and shake with ice until very cool. Then double-strain into the prepared copper mug over ice and top it up with the ginger beer. Stir with a cocktail spoon and garnish with another mint sprig. As cucumber goes beautifully with many types of gin, you may like to add a cucumber ribbon. But we cannot stress this enough: Mixology is to a great extent about creativity. Take the ideas and recipes we gave you and make them your own. Everything depends on your knowledge, your options and your preferences!