01 - Whisk together flour, baking powder, and salt in a medium bowl. Set aside for later use.
02 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 2-3 minutes.
03 - Mix in egg and vanilla extract until fully incorporated into the butter mixture.
04 - Gradually add dry ingredients to wet mixture, beating on low speed until dough forms.
05 - Divide dough in half, flatten into discs, wrap in plastic, and refrigerate for minimum 1 hour.
06 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
07 - On floured surface, roll dough to 1/4 inch thickness. Cut heart shapes and place 1 inch apart on prepared sheets.
08 - Bake for 8-10 minutes until edges begin turning golden. Cool on sheet 5 minutes, then transfer to wire rack.
09 - Combine powdered sugar and meringue powder. Add 3 tablespoons water and beat on low until stiff peaks form, about 5 minutes. Adjust consistency with additional water if needed.
10 - Divide icing and tint with gel food coloring. Transfer to piping bags and decorate cooled cookies. Let set at room temperature until dry, approximately 1 hour.