Preheat the oven to 350° F.
In a medium sized mixing bowl, add in the flour and baking powder. Stir the ingredients to combine them.
In the stand mixer, cream the salted butter and sugar together until all of the butter lumps are gone.
Add in the egg and vanilla extract and mix until just combined.
Slowly add the flour and baking powder mixture into the wet ingredients until the dough forms a ball. If the ball is very sticky, add another tablespoon of flour.
Roll the dough onto a floured surface or piece of parchment paper and use the heart cookie cutter to cut out the cookies.
Place the cut out cookies onto a cookie sheet lined with a silicone mat. Do not overcrowd the pan. Bake for 7-9 minutes or until the center of the cookies do not appear wet.
Allow the cookies to cool for 5 minutes on the baking sheet before transferring them to a piece of parchment paper. Repeat the cookie baking process for all remaining cookies.