Dice the butter and put it into a mixing bowl to soften. Sift the flour on top with the caster sugar, a pinch of salt and the vanilla extract. Rub together gently and form into a ball. Alternatively, blitz all the ingredients in a food processor until they ball. The mixture needs no liquid.
Shake some sugar on a surface, put the dough on it and cut in half, shaping into 2 equal balls. P