Preheat your oven to 350°F (175°C).
In a large mixing bowl, cream together the softened butter and sugar until light and fluffy.
Add the egg and vanilla extract to the creamed mixture and mix until well combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Chill the dough in the refrigerator for about 30 minutes, allowing it to firm up.
Roll out the dough on a floured surface to about 1/4-inch thickness.
Cut out heart shapes using a cookie cutter and place them on a baking sheet lined with parchment paper.
Bake for 8-10 minutes, or until the edges begin to turn golden.
Allow the cookies to cool on the baking sheet for a few minutes before transferring to a wire rack.
Decorate with icing or sprinkles as desired once completely cool.
