1. Prepare the Dough

• In a large mixing bowl, use a hand mixer or stand mixer to cream the softened butter, granulated sugar, and powdered sugar until light and fluffy.
• Beat in the eggs, one at a time, until fully incorporated. Add the vanilla extract and mix well.

2. Combine the Dry Ingredients

• In a separate bowl, whisk together the all-purpose flour, baking powder, and salt.
• Gradually add the dry ingredients to the wet mixture, mixing until just combined. Avoid overmixing to maintain a tender cookie texture.

3. Divide and Color the Dough

• Divide the dough into three equal portions.
• Leave one portion plain (white). Add red gel food coloring to the second portion and green gel food coloring to the third portion, mixing until the colors are evenly distributed and vibrant.

4. Roll Out the Dough

• Roll each portion of dough into a rectangular shape (approximately 1/4 inch thick) on parchment paper.
• Layer the green dough on top of the red dough, followed by the plain dough, pressing gently to ensure the layers stick together.

5. Form the Pinwheel

• Using the parchment paper to guide you, tightly roll the layered dough into a log, starting from one long edge.
• Wrap the log in plastic wrap and refrigerate for at least 1–2 hours, or until firm.

6. Coat with Nonpareils

• Spread the holiday-colored nonpareils on a flat surface.
• Roll the chilled dough log in the nonpareils, pressing gently so they adhere to the dough.

7. Slice and Bake

• Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper.
• Slice the dough log into 1/4-inch thick rounds and place them on the prepared baking sheets, spacing them about 1 inch apart.
• Bake for 10–12 minutes, or until the edges are just set.
• Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.