In large mixing bowl, beat together 2 cups of the powdered sugar, the pecans, butter, and creme de menthe. Beat or stir in remaining powdered sugar. Cover and chill mixture for 1 hour or until firm.
Shape into 1-inch balls. Place balls on a foil- or waxed-paper-lined baking sheet. Chill for 15 minutes.
In a small, heavy saucepan, heat chocolate pieces and shortening over very low heat, stirring constantly, until chocolate melts.
Dip one side of each of the chilled balls into melted chocolate. Return to baking sheet. Chill until set. Makes about 60 candies.
For a non-alcoholic candy, use 1/4 cup corn syrup, 1/4 teaspoon peppermint extract, and a few drops green food coloring for creme de menthe.
Prepare candies as above. Cover and store in refrigerator for up to 1 week. Or freeze candies in a freezer container for up to 3 months.