To sugar frost the glass, rub the rim with a lime wedge and dip it into the vanilla sugar. Place the cracked ice cubes into a cocktail shaker. Pour over the vodka, lime juice and vanilla sugar. Shake vigorously until a frost forms on the outside of the glass. Half-fill a long glass with the extra cracked ice cubes and strain the mixture over them. Top with the ginger beer and garnish with a lime wedge.