christmas cookies recipe

225g / 1 cup unsalted butter , softened (or use salted, skip salt) ▢1 cup caster/superfine sugar (granulated/ordinary white sugar ok too) ▢1 1/2 tsp vanilla extract ▢1 large egg (55-60g / 1.9-2oz) ▢3 cups flour , plain / all purpose ▢3/4 tsp baking powder ▢3/4 tsp salt