Melt chocolate with butter in top of double-boiler. Cool to room temperature. Meanwhile, beat goat cheese with icing sugar, jam and espresso powder until light and fluffy. Mix in melted chocolate mixture. Chill 2 hr. or until firm.
Roll heaping teaspoons of goat cheese mixture into balls. Then roll in pistachios to coat. Place truffles on baking sheet. Chill 1 hr., or until firm, before serving. Store refrigerated in airtight container 3 to 5 days.
Instead of nut coating, roll in cocoa powder or dip in melted chocolate.