Beat butter at medium speed of an electric mixer until creamy; gradually add sugars, beating well. Add egg substitute and vanilla; beat well. Add flour to butter mixture; beat well. Stir in miniature chocolate morsels and chopped pecans. Cover and chill 30 minutes.
Shape mixture into 1" balls. Cover and freeze balls until very firm.
Place (12-ounce) package morsels and shortening in a 1-quart glass bowl; melt in microwave according to package directions. Using two forks, quickly dip frozen truffles into melted chocolate, coating completely. Place on wax paper to harden. Store truffles in refrigerator 2 to 3 days.