Place a handful of ice cubes in a copper cup. (You can use a glass tumbler if you do not have a copper cup available, but for the ultimate mule experience, a copper cup is preferable.) Pour ginger beer over the ice, followed by the 2 ounces of vodka. Crush the mint leaves and drop them into the drink followed by a twist of lime and the vanilla. Stir. Garnish with a lime slice and a sprig of mint and enjoy!