01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a small bowl, combine ground flaxseed with water and let sit for 5 minutes until thickened.
03 - In a large bowl, beat vegan butter, granulated sugar, and brown sugar until light and fluffy.
04 - Add flax egg, plant-based milk, vanilla extract, and peppermint extract to butter mixture. Mix until fully incorporated.
05 - In a separate bowl, whisk together flour, baking soda, baking powder, and salt.
06 - Gradually fold dry ingredients into wet mixture, stirring until just combined.
07 - Divide dough in half. Add red or green food coloring to one half and mix until evenly tinted. Leave other half plain.
08 - Pinch small pieces from both dough portions and gently twist together to create marbled effect. Roll into 1-inch balls and place 2 inches apart on prepared baking sheets.
09 - Gently flatten each ball. Sprinkle tops with crushed peppermint candies and vegan white chocolate chips if desired.
10 - Bake for 10 to 12 minutes until edges are set but centers remain soft.
11 - Cool on baking sheets for 5 minutes, then transfer to wire rack for complete cooling.