1. Prepare the Crust:

1. In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the egg and vanilla extract.
2. In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until a soft dough forms.
3. Divide the dough in half. Mix red food coloring into one half until the color is uniform. Leave the other half plain.
4. On separate pieces of parchment paper, roll each dough half into a 9×7-inch rectangle. Place the red dough rectangle on top of the plain one. Using the parchment to help, tightly roll the dough into a log. Wrap and chill for at least 2 hours.
5. Preheat oven to 375°F (190°C). Slice the log into 1/4-inch thick rounds and place on ungreased baking sheets. Bake for 8-10 minutes or until set. Let cool on the pan for 5 minutes before transferring to a wire rack.