Preheat your oven to 350°F (175°C).
In a bowl, whisk together flour, baking powder, and salt.
In a separate large bowl, cream the softened butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the egg and vanilla extract until well combined.
Gradually add the dry mixture to the wet ingredients, mixing until just combined.
Chill the dough in the refrigerator for at least 30 minutes.
Roll out the chilled dough on a floured surface to about 1/4 inch thick.
Cut out heart shapes using cookie cutters.
Place cookies on a baking sheet lined with parchment paper.
Bake for 10-12 minutes until edges start to golden.
Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.
Once completely cooled, decorate with royal icing.
