01 - Combine softened butter and granulated sugar in a large mixing bowl. Beat with an electric mixer until light and fluffy, approximately 2 minutes.
02 - Add the egg and vanilla extract to the creamed mixture, blending until fully combined.
03 - In a separate bowl, whisk together all-purpose flour, baking powder, and salt.
04 - Gradually add the dry ingredients to the wet mixture. Mix with the mixer on low speed until just combined and a soft dough forms.
05 - Equally divide the dough into three portions. Tint one with blue gel food coloring, the second with red, and the third with green by kneading until the color is uniformly distributed.
06 - Wrap each colored dough portion with plastic wrap and refrigerate for a minimum of 1 hour.
07 - Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
08 - Break off pieces of each colored dough, measuring about 1 tablespoon per portion. Roll into ropes approximately 5 inches long. Twist two ropes of different colors together and gently pinch the ends sealed. Arrange on the prepared baking sheets, repeating with remaining dough.
09 - Optionally, sprinkle shaped cookies with festive sprinkles before baking.
10 - Bake for 10-12 minutes, or until edges are just turning golden.
11 - Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. Finish with a light dusting of powdered sugar if desired.