In a large mixing bowl, cream together the butter, sugar, and vanilla extract on medium speed until the mixture is light and fluffy (about 3 minutes).

Add eggs one at a time, beating just until combined.

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

Gradually add the dry mixture to the wet mixture in 3–4 batches. Mix until a dough forms. If it seems too wet, add 1–2 tablespoons more flour.

Set aside about 2/3 of the dough. To the remaining 1/3, mix in a few drops of food coloring until the desired shade is reached.

Freeze the colored dough for 5 minutes, then roll it out on a floured surface to 1/2-inch thickness. Freeze again for 20 minutes.

Use a small heart-shaped cookie cutter to cut out hearts. Lightly dampen each one to help them stick, stacking into a log about 10 inches long.

Freeze the log of hearts for at least 30 minutes until solid.

Press the plain dough evenly around the heart log, forming a smooth cylinder. Wrap in plastic wrap and chill for 30 minutes.

Preheat oven to 350°F. Line two baking sheets with parchment paper.

Slice the dough log into 1/4-inch rounds and space them 2 inches apart on the baking sheets.

Bake for 12 minutes, or until the bottoms are golden. Cool completely before serving.