Cream butter and sugar in a large bowl until fluffy and pale, about 4 minutes.
Add eggs one at a time, mixing well after each. Stir in vanilla extract.
Whisk flour, baking powder, and salt in a separate bowl. Fold into wet ingredients until just combined.
Divide dough in half. Color one portion pink with food coloring, kneading until evenly distributed.
Roll pink dough to ½-inch thickness. Cut out heart shapes with 1.5-inch cookie cutter. Press hearts together to form a log.
Freeze heart log for 20 minutes until firm.
Roll plain dough into a ¼-inch thick rectangle. Place frozen heart log in center and wrap plain dough around it, sealing seam.
Wrap tightly in plastic wrap and freeze for at least 1 hour.
Preheat oven to 350°F. Line baking sheets with parchment paper.
Slice frozen dough log into ¼-inch rounds using a sharp knife. Place cookies 2 inches apart on prepared sheets.
Bake for 10-12 minutes until edges are golden. Centers may look slightly underdone.
Cool on baking sheet for 5 minutes before transferring to wire rack.
