Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a bowl, whisk together flour, baking powder, and salt.

In another bowl, cream together softened butter, granulated sugar, and powdered sugar until light and fluffy.

Add egg yolk and vanilla extract; mix until combined.

Gradually add dry ingredients to wet mixture until just blended.

Roll out dough to 1/4-inch thickness and cut into heart shapes using cookie cutters.

Place on prepared baking sheets and bake for 10-12 minutes or until lightly golden around the edges.