Cream together the butter and sugar until smooth.
Beat in eggs and vanilla extract.
Stir in the flour, baking powder, and salt.
Pat the ball of dough into a flat disc, wrap in plastic wrap and chill in the fridge for at least one hour (or overnight).
Preheat oven to 200°C.
Roll out dough until 1/2 - 1cm thick. I like to roll between 2 sheets of baking paper so that the dough doesn't stick, and no additional flour is incorporated into the dough.
Cut into heart shapes using your cookie cutters.
Place cookies 3cm apart on cookie sheets lining with baking paper.
Bake for around 8 minutes until lightly golden.
Allow to cool completely before icing.