Cream together butter and powdered sugar in a large bowl. Add peppermint extract, egg yolks, and food coloring, then mix in flour, baking powder, and salt. Shape into 1-inch balls on a parchment-lined sheet, creating wells with a wooden spoon.
Bake at 350 degrees for 8-10 minutes, reshape wells, and cool on a rack. In a small bowl, melt dark chocolate chips, whipping cream, and butter. Fill wells with chocolate, top with a mint, and let set. Enjoy the delicious cookies!