01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly distributed.
03 - In a large mixing bowl, beat the softened unsalted butter, granulated sugar, and packed light brown sugar using an electric mixer until the mixture is light and fluffy, approximately 2 to 3 minutes.
04 - Add the large egg, vanilla extract, and cotton candy flavoring to the creamed mixture. Beat until all ingredients are fully combined and the batter is smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until the dough just comes together. Avoid overmixing to keep the cookies tender.
06 - Divide the dough evenly into two separate bowls. Add pink gel food coloring to one bowl and blue gel food coloring to the other. Fold each gently until soft pastel shades are achieved throughout.
07 - Pinch off a small portion from each colored dough and gently press them together to form a swirled, multi-colored ball. Arrange on the prepared baking sheets, spacing each ball about 2 inches apart. If desired, roll each dough ball in colored sprinkles before placing on the sheet.
08 - Bake for 9 to 11 minutes, or until the edges are just set and the centers appear slightly underbaked. The cookies will continue to firm up as they cool.
09 - Allow the cookies to rest on the baking sheets for 5 minutes, then carefully transfer to a wire cooling rack to cool completely before serving or storing.