Place chocolate in a medium heatproof bowl. In a small pan over medium heat, bring heavy cream just to a simmer. Pour the cream over the chocolate; let stand 1 minute. Stir until smooth. (If the chocolate hasn't quite melted, set the bowl in a skillet of simmering water.) Cover and chill until just firm, about 2 hours. Using a 1/2-oz. ice cream scoop or a tablespoon measure, scoop up the ganache and roll into balls. Place on a rimmed baking sheet lined with parchment or wax paper and chill until firm, about 30 minutes.
The Do's and Don'ts of Cooking with Chocolate