Preheat oven to 350 degrees.
1. Butter and line an 8-inch square baking pan with parchment paper, leaving an overhang on all sides, butter parchment.
2. Place chocolate and butter in a bowl and microwave until melted, stirring often so not to burn.
3. Remove from the microwave. Whisk in sugar, peppermint extract and salt until smooth; whisk in eggs. Gently whisk in flour and cocoa powder just until smooth (do not over mix).
4. Spread batter in prepared pan and top with crushed peppermint candies. Bake until a toothpick inserted in center comes out clean approximately 30-25 minutes.
5. Cool completely in pan. Cut into squares.