01 - Preheat the oven to 350°F (175°C). 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, about 2 to 3 minutes.
04 - Add the large egg, vanilla extract, and cotton candy flavoring to the butter mixture. Beat until fully combined and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. 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. Gently fold each portion until soft pastel shades are achieved.
07 - Pinch off a small piece of dough from each colored portion and gently press them together to form a swirled, multi-colored ball. Place each ball on the prepared baking sheet, spacing them about 2 inches apart. Optionally, roll each ball in colored sprinkles before placing on the sheet.
08 - Bake for 9 to 11 minutes, until the edges are just set and the centers appear slightly underbaked. Remove from the oven promptly to maintain a soft texture.
09 - Allow the cookies to rest on the baking sheet for 5 minutes, then transfer them to a wire cooling rack to cool completely before serving or storing.