Caipirinha
Mojito fans in particular will love this light, zesty yet punchy cocktail from Brazil. It's made with just three ingredients - cachaça, lime and sugar.
Put the sugar in a pan with 100ml of water and stir over a low heat until the sugar has dissolved. Cool completely and pour into a sterilised bottle – this sugar syrup will keep in the fridge for up to a month.
Put the gin, lemon juice, 1 tbsp of the sugar syrup and egg white, if using, in a cocktail shaker with ice. Shake vigorously for 15 seconds then strain into a chilled collins glass and top with sparkling water. Garnish with a slice of lemon.