How to Make It
Beat butter with a heavy-duty stand mixer on medium speed until creamy, about 2 minutes; gradually add sugar, beating well. Add egg and extracts, beating until combined.
Stir together flour, baking powder, and salt in a small bowl. Gradually add to butter mixture, beating on low speed just until blended.
Divide dough in half; add desired amount of red food coloring to 1 portion, and knead until color is distributed. Shape dough halves into disks; wrap in plastic wrap, and chill until firm, about 1 hour.
Divide each half of dough into 2 equal portions. Roll out each portion on floured wax paper into an 8-inch square, trimming edges if necessary.
Invert 1 white dough square onto 1 red dough square; peel wax paper from white dough. Tightly roll up dough, jelly-roll fashion, peeling wax paper from red dough as you roll. Repeat with remaining dough squares. Wrap rolls in plastic wrap, and chill 2 hours.
Preheat oven to 350°F. Remove dough from refrigerator, and cut into 1/4-inch-thick slices; place slices 2 inches apart on parchment paper-lined baking sheets. (Keep unbaked dough chilled while baking cookies.)
Bake, in batches, in preheated oven until bottoms are lightly browned, 10 to 12 minutes. Remove cookies from pans to wire racks, and cool completely.