01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the gluten-free flour, baking soda, baking powder, and salt until well combined.
03 - In a large bowl, cream the softened butter with granulated sugar and brown sugar using an electric mixer until light and fluffy, about 2-3 minutes.
04 - Beat in the egg, vanilla extract, and peppermint extract until the mixture is smooth and well combined.
05 - Gradually mix the dry ingredients into the wet mixture, mixing on low speed until just combined. Do not overmix.
06 - Gently fold in white chocolate chips, semi-sweet chocolate chips, and crushed peppermint candies until evenly distributed throughout the dough.
07 - Scoop tablespoon-sized balls of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
08 - If desired, sprinkle extra crushed peppermint candies on top of each dough ball for festive decoration.
09 - Bake for 11-13 minutes, or until edges are set and centers look slightly underbaked. They will continue cooking on the hot baking sheet.
10 - Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before storing or serving.