01 - Preheat oven to 350°F and line a baking sheet with parchment paper.
02 - In a medium bowl, whisk together almond flour, coconut flour, erythritol, baking powder, and salt until well blended.
03 - In a large bowl, cream the softened butter until light and fluffy. Add the egg, vanilla extract, and peppermint extract. Beat until thoroughly combined.
04 - Gradually incorporate the dry ingredients into the wet mixture, stirring until a soft, cohesive dough forms.
05 - For visual appeal, divide dough in half. Tint one portion with red gel food coloring and knead until evenly colored. Twist small pieces from each portion together to create a marbled effect.
06 - Roll dough into 1-inch balls and arrange on the prepared baking sheet, leaving 2 inches of space between each. Gently flatten with your palm or the bottom of a glass.
07 - Press sugar-free white chocolate chips into the cookie tops and sprinkle with crushed peppermint candies, if using.
08 - Bake for 10 to 12 minutes, until edges begin to turn golden brown. Allow cookies to rest on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.