Very smooth, very rich, very yum...
These truffles are adapted from an original recipe by Kay Hartman, as posted to rec.food.cooking. Thank you for sharing these with us, Kay!
Cut chocolate into smallish chunks (unless you are using chocolate chips) and place in food processor. Process until finely ground. Add 1/4 cup walnuts and brown sugar, and process until nuts are finely ground.
In microwave, heat cream until just boiling (takes 2-2.5 minute at high). Turn food processor on, and add cream through feed tube. Add the liqueur in the same fashion.
Pour into a bowl, cover, and chill for several hours.
Remove from refrigerator, and drop by spoonfuls onto a wax paper lined cookie sheet (size of "spoonfuls" depends on what size truffles you want).
Return to refrigerator for at least one hour.
In food processor, process the 2 cups of walnuts, the 1/4 cup powdered sugar, and the 1/4 cup cocoa, until walnuts are finely ground. Place in a bowl.
Remove the truffles from the refrigerator. Coat hands with powdered sugar so that the truffles do not stick to your hands; shape each truffle into a ball, and then roll in the walnut/cocoa/sugar mixture.
Return to refrigerator. At this point the truffles may be served, although I prefer to dip them in melted semisweet chocolate first.