Preheat your oven to 350°F (175°C) to ensure even baking.
Line your 9x9 inch baking pan with parchment paper, leaving some overhang for easy removal.
In a medium saucepan over low heat, melt the unsalted butter and bittersweet chocolate chips until smooth. Remove from heat and let cool slightly.
Add granulated sugar and brown sugar to the chocolate mixture and whisk until well combined.
Crack in the eggs one at a time, whisking thoroughly after each addition. Stir in the pure vanilla extract until smooth and glossy.
In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, and salt.
Gently fold the dry ingredients into the chocolate mixture using a spatula, being careful not to overmix.
Stir in the crushed peppermint candy canes, reserving some for topping.
Pour the brownie batter into the prepared baking pan, spreading evenly and sprinkling reserved candy canes on top.
Bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Cool in the pan for about 10 minutes, then lift out using the parchment paper and let cool completely on a wire rack before cutting into squares.
