In small saucepan, combine all ingredients except unsweetened cocoa; mix well. Cook over low heat until chocolate is melted and mixture is smooth, stirring constantly. Place saucepan in bowl of ice water to speed chilling, stirring mixture occasionally. With small strainer, sift light layer of cocoa onto cookie sheet.
When chocolate mixture is cooled and slightly thickened, spoon into decorating bag fitted with desired decorative tip.* Squeeze small 1-inch truffles onto cocoa-dusted cookie sheet. Sift remaining cocoa over truffles. Store in refrigerator. Let truffles stand at room temperature for 30 minutes before serving.