Preheat oven to 325ºF. Line 2 baking sheets with parchment paper or silicone baking mats. Set aside.
In a small bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt; set aside. 1 cup all-purpose flour
1 cup all-purpose flour, ½ cup unsweetened cocoa powder, 1 teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon salt
In a separate bowl, whisk together brown sugar, eggs, and peppermint extract until thoroughly combined; set aside. 1 ½ cups dark brown sugar
1 ½ cups dark brown sugar, 3 large eggs, 1 teaspoon peppermint extract
In a microwave-safe bowl, combine chopped chocolate and butter. 4 ounces unsweetened chocolate baking barsMicrowave at 50 percent power, stirring occasionally, until melted, 2 to 3 minutes. 4 ounces unsweetened chocolate baking bars, 4 tablespoons unsalted butter
Whisk melted chocolate mixture into egg mixture until combined.
Fold in flour mixture using a rubber spatula or wooden spoon until no dry streaks remain.
Stir in peppermint chunks. 1 cup white chocolate peppermint chunks Let dough sit at room temperature for 10 minutes. Meanwhile, place crushed candy canes in a separate shallow dish. ½ cup crushed candy canes
½ cup crushed candy canes
Scoop out 2 tablespoons of dough and roll between palms into a smooth ball. Lightly dip top of dough ball into crushed candy canes or sprinkle crushed candy canes on top of dough. Transfer dough ball to prepared baking sheet and repeat with remaining dough, being sure to evenly space dough balls on prepared sheets. Place cookie sheets into oven, 1 sheet at a time, until puffed and edges have begun to set but centers are still soft (cookies will seem underdone), about 12 minutes, rotating sheet halfway through baking. Let cool completely on sheet before serving.