In a medium bowl, whisk together flour, baking powder, and salt until well combined. Set aside.

Cream softened butter and granulated sugar until light and fluffy. Beat in egg, vanilla, and peppermint extract until incorporated.

Gradually add dry mixture to creamed butter and sugar, mixing on low until just combined. Divide dough in half.

Mix red gel food coloring into one half of the dough. Wrap each portion in plastic wrap and chill for at least 30 minutes.

Roll out each dough portion into a rectangle, stack red dough on top of plain, aligning edges.

Roll the layered dough tightly into a log, wrap in plastic wrap, and chill for at least 2 hours.

Preheat the oven to 375°F (190°C) and line baking sheets with parchment paper.

Slice the chilled dough log into 1/4-inch rounds, brush with egg white or water, and roll in coarse sugar or crushed candies.

Bake for 8-10 minutes until edges are lightly golden. Cool on baking sheets for a few minutes before transferring to a wire rack.