Heat chocolate and cream in the top of a double boiler over simmering water without stirring for 3 minutes. Whisk chocolate and cream together until smooth. Remove from heat and let mixture cool until thick, 20 to 30 minutes.
Pour chocolate mixture into a flat baking dish, cover with plastic wrap, and chill until fully set, about 3 hours.
Place chopped peppermint candies into a shallow bowl. Use a melon baller to scoop about 1 1/2 teaspoon of chocolate mixture; form into a ball-shaped truffle and set aside on a piece of parchment paper on a work surface. Roll truffles in peppermint candy and lightly roll truffles between your hands to press candy pieces into truffles.