01 -
In a large bowl, use an electric mixer on medium speed to cream the butter and sugar together until smooth and fluffy.
02 -
Add the eggs and vanilla extract to the creamed mixture and beat until fully combined.
03 -
In a separate medium bowl, whisk together the flour, baking powder, and salt.
04 -
Gradually add half of the dry ingredients to the wet ingredients and mix until combined, then add the remaining dry ingredients and mix until fully incorporated.
05 -
Divide the dough evenly into two bowls. Add green gel food coloring to one portion and knead until uniformly colored; repeat with purple gel food coloring for the other portion.
06 -
Shape each colored dough into a ball, wrap tightly in plastic wrap, and refrigerate for at least one hour.
07 -
Lightly dust the countertop or cutting board and rolling pin with flour to prevent sticking.
08 -
Unwrap the purple dough, lightly dust with flour, and roll into a rectangle. Repeat with the green dough.
09 -
Use a rubber spatula to lift the green dough and place it atop the purple dough. Lightly roll the layered dough together, then trim edges to form a neat rectangle.
10 -
Carefully roll the layered dough into a log, wrap tightly with plastic wrap covering all ends, and refrigerate for one hour until firm.
11 -
Preheat the oven to 325°F and line a baking sheet with parchment paper.
12 -
Remove the dough log from the refrigerator, unwrap, and discard the ends. Slice the log into 1/4 to 1/2 inch thick rounds.
13 -
Place the cookie slices two inches apart on the prepared baking sheet. Bake for 13 to 15 minutes until set, checking at 10 minutes to avoid browning.
14 -
Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.