Line a baking sheet with parchment paper and set aside. Using a double boiler, melt the chocolate until it is a smooth consistency. Add in the peppermint extract and stir. Fold in 1/2 of the crushed candy canes. Pour the chocolate mixture onto the baking sheet into a thin layer. Sprinkle the rest of the crushed candy canes on top. Refridgerate for 1-2 hours until cooled and solid. Break into smaller pieces.