Finely crush cookies in a food processor or in a heavy plastic bag with a rolling pin or meat mallet (there should be about 1-1/3 cups).
Set aside 2 tablespoons of the crushed cookies; stir remaining crushed cookies into chocolate mixture, mixing well.
Chill in refrigerator 10 minutes, stirring once after 5 minutes. (Do not chill longer as mixture will become too hard to spoon out).
Spoon a heaping teaspoon of the mixture into mounds onto a sheet of waxed paper. (If mixture is too wet, stir in 1 tablespoon additional cookie crumbs at a time).Let stand at room temperature 20 minutes to “air dry”.
Place powdered sugar in a small bowl. Pick up each teaspoon of the mixture and shape into a ball or rough truffle shape. Place in bowl of powdered sugar; use 2 forks to toss until well coated with sugar.
Place in individual paper or foil candy cups or on a serving plate. Store at room temperature.