Begin by removing the refrigerated sugar cookie dough from its packaging. In a large mixing bowl, combine the dough with 1/3 cup of flour. This will help you roll out the dough more easily and achieve the right consistency.
Once the dough is well mixed, divide it into four equal portions. This will allow you to create the different colors of your rainbow.
Color each portion of dough using food coloring. Start with a few drops of each color, kneading the dough until the color is evenly distributed. Aim for red, orange, yellow, green, blue, and purple to create a classic rainbow effect.
Take each colored dough portion and roll it out on a lightly floured surface into rectangles about 1/4 inch thick. Make sure to keep the thickness consistent for even baking.
Once you have your colored rectangles, stack them on top of each other starting with the red on the bottom, followed by orange, yellow, green, blue, and purple. Press them gently together to ensure they stick.
Using the parchment paper to help, carefully roll the stacked dough into a tight log. Make sure to roll from one end to the other, keeping the log as tight as possible for defined swirls.
Wrap the log in plastic wrap and refrigerate for at least 1 hour. This will firm up the dough, making it easier to slice.
While the dough is chilling, preheat your oven to 350°F (175°C). Line your baking sheets with parchment paper.
After chilling, remove the log from the refrigerator and slice it into 1/4 inch thick rounds. You should see beautiful pinwheel designs in each slice.
Roll the edges of each cookie in rainbow colored sugar to add a sweet crunch and extra flair.
Place the sliced cookies on the prepared baking sheets, leaving some space between each one. Bake for 10-12 minutes or until the edges are lightly golden.
Once baked, allow the cookies to cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely. Enjoy your vibrant, delicious Rainbow Pinwheel Cookies!