01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, cocoa powder, baking soda, salt, and espresso powder in a medium bowl. Set aside.
03 - Using an electric mixer, cream softened butter with granulated and brown sugar until light and fluffy, about 2 minutes.
04 - Add eggs one at a time, beating well after each. Mix in vanilla and peppermint extracts.
05 - Gradually add dry ingredients to wet mixture, stirring until just combined.
06 - Gently fold in semisweet chocolate chips, white chocolate chips, and crushed peppermint candies.
07 - Drop rounded tablespoons of dough about 2 inches apart onto prepared baking sheets.
08 - Bake for 9 to 11 minutes until edges are set but centers remain soft. Avoid overbaking.
09 - Let cookies cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.
10 - Optionally, drizzle cooled cookies with melted white chocolate and sprinkle with additional crushed peppermint candies.