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. Set aside.
03 - In a large mixing bowl, beat the softened butter, granulated sugar, and light brown sugar with an electric mixer until pale, light, and fluffy, about 3 minutes.
04 - Add the eggs one at a time, mixing well after each addition. Blend in the vanilla extract and cotton candy flavoring until the mixture is smooth and homogeneous.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until a soft, cohesive dough forms. Do not overmix.
06 - Divide the dough evenly into two separate bowls. Add a few drops of pink gel food coloring to one portion and blue gel food coloring to the other. Fold and mix each until the color is uniform throughout.
07 - Pinch off a small amount of dough from each colored portion and gently press and swirl them together in your palms to form a 1.5-inch ball with a marbled appearance. Arrange on the prepared baking sheets, spacing them 2 inches apart.
08 - Bake for 9 to 11 minutes, or until the edges are just set while the centers remain soft and slightly underbaked.
09 - Allow the cookies to rest on the baking sheets for 5 minutes to firm up, then transfer them to a wire cooling rack to cool completely.
10 - Just before serving, top each cooled cookie with a small tuft of cotton candy for a whimsical, colorful finish. Add the garnish right before serving as cotton candy dissolves quickly on contact with moisture.