01 - Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving overhang for easy removal.
02 - Melt butter and semisweet chocolate in a microwave-safe bowl using 30-second intervals, stirring until smooth and let cool slightly.
03 - Whisk sugar, eggs, vanilla extract, and peppermint extract into the melted chocolate mixture until fully incorporated.
04 - Sift together all-purpose flour, unsweetened cocoa powder, and salt, then gently fold into the wet mixture until just combined.
05 - Pour batter into the prepared pan, smooth the surface, and bake for 28 to 32 minutes until a toothpick inserted comes out with moist crumbs; avoid overbaking.
06 - Allow brownies to cool completely in the pan placed on a wire rack before applying glaze.
07 - Whisk powdered sugar, milk, and peppermint extract until smooth. Add food coloring if desired.
08 - Spread the glaze evenly over cooled brownies and sprinkle with crushed peppermint candies.
09 - Let the glaze set for 20 minutes, then lift brownies from the pan using parchment overhang and cut into 16 squares.