01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly distributed.
03 - In a large bowl, beat the softened unsalted butter, granulated sugar, and packed light brown sugar using an electric mixer until the mixture is light and fluffy.
04 - Beat in the egg, vanilla extract, and cotton candy flavoring until well combined and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Do not overmix.
06 - Divide the dough evenly into two bowls. Add pink gel food coloring to one bowl and blue gel food coloring to the other, folding gently to achieve soft pastel shades.
07 - Pinch off a small piece from each colored dough and gently press them together to form a swirled multi-colored ball. Place on the prepared baking sheets, spacing each ball about 2 inches apart. Optionally, roll each dough 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 still appear slightly underbaked for a soft texture.
09 - Let the cookies rest on the baking sheets for 5 minutes, then transfer to a wire cooling rack to cool completely before serving or storing.