1. In a bowl, melt chocolate chips and butter. Stir in vanilla, slivered almonds, walnuts, and dried fruit. Chill mixture for 1 hour. Place half the chocolate mixture on a large piece of plastic wrap, forming a rough log as you go. Wrap with plastic, then roll to finish molding. Twist ends of plastic wrap and refrigerate until very firm, about 45 minutes. Repeat with remaining chocolate mixture. Unwrap and dredge each log in powdered sugar. Remove excess, then slice into 1/4-inch rounds.