In a mixing bowl, beat eggs, sugar and vanilla until well mixed.  Add butter and shortening.  Separately, combine flour, cocoa and salt; stir into egg mixture and mix well.  Add nuts, if desired.  Line a 13-in x 9-in pan with foil and grease the foil; pour in the batter. Bake at 350 degrees for 30 minutes.  Turn brownies out of plan onto a cookie sheet; remove foil.  Cut with a star cutter or into bars.  Makes about 3 dozen.