Add the flour, baking powder, and salt to a large mixing bowl. Stir with a fork to combine and set aside.

In a separate large mixing bowl, cream together the butter and sugars using a mixer. Beat until smooth.

Add the egg and vanilla and mix again until smooth.

Fold in the dry ingredients, half at a time, and mix until a thick, smooth dough forms.

Divide the dough into three equal portions. Add food coloring to each: red, green, and white (original). Mix until solid colors develop.

Roll each colored dough flat about ¼ inch thick on a floured surface.

Layer the dough sheets (red, white, green) and cut into a 9x13 inch rectangle. Roll tightly from one long side and seal edges.

Wrap the log in plastic wrap and refrigerate for 2 hours.

Preheat oven to 350°F. Slice the chilled dough into ½ inch cookies and place on parchment-lined baking sheets.

Bake for 13-15 minutes until just set. Cool on wire racks before serving.