In a lg. mixing bowl, combine condensed milk & peppermint extract. Beat in enough confectioners sugar, a little at a time, to form stiff dough that is no longer sticky.
Form into 1" balls, then place on waxed paper and flatten with fingers to form "patties". Place in Freezer for 1 hour.
In med. saucepan, over low heat, melt chocolate with shortening stirring often. Remove from heat. Dip patties, one at a time into chocolate by laying them on the tines of a fork and lowering fork into the liquid.
place back on wax paper and put in fridge to let chocolate set.