Preheat oven to 350F (325 convection bake). Line 2 baking sheets with parchement paper. Set aside.
In a medium bowl, whisk together flour, cocoa, baking powder, espresso powder and salt. Set aside.
In a small, heat-safe bowl, combine chocolate (chips or chopped pieces) with butter. In the microwave (or over a double boiler), melt mixture until smooth and glossy. Allow mixture to cool while you continue with the next step.
In a large bowl, combine eggs with sugar and extracts (vanilla and peppermint). Vigorously beat egg mixture until doubled in volume, smooth, and pale yellow in colour (note: if using an electric mixer, mix at medium-high setting for approx. 5 minutes).
Add slightly cooled melted chocolate mixture to the whipped egg mixture and stir to combine. Finally, add flour mixture into chocolate batter. Stir to combine.
Using a small/medium cookie scoop, scoop approx. 2 tsp of cookie batter onto lined baking sheet, spacing spoonfuls ~2" apart.
Sprinkle tops of brownie cookies with crushed candy cane pieces.
Bake cookies at 350F for ~13 min, or until the surface of each cookie has become cracked, glossy, and is firm at the edges. Allow cookies to cool completely on a baking sheet (at least 10 min).
Enjoy!