In a saucepan, let 6 ounces chocolate with butter, cream, and jam, over hot, not simmering, water, stirring constantly until smooth.
Remove from heat and stir in liqueur/extract.
Chill, covered, for 2 hours, or until firm.
Form mixture by heaping teaspoons into balls and roll in cocoa powder.
Chill in freezer on a baking sheet lined with wax paper for 1 hour, or until firm.
Melt remaining 6 ounces of chocolate with shortening until smooth. Dip frozen truffles into chocolate to coat and refrigerate until firm.
Store in an airtight container in the refrigerator for up to 1 month or in the freezer for up to 3 months.