In a double boiler, melt the chopped semisweet chocolate with the heavy cream, stirring until smooth.

Remove from heat and stir in the peppermint extract.

Allow the mixture to cool to room temperature, then refrigerate for about 30 minutes until firm.

Using a melon baller or your hands, scoop out small amounts of the chilled chocolate mixture and roll into balls.

Roll each truffle in cocoa powder or crushed peppermint candies to coat.

Place the coated truffles on a baking sheet lined with parchment paper and refrigerate until firm, about 15 minutes.

Serve chilled or at room temperature.