In mixing bowl beat shortening and butter together with electric mixer, then add the sugars and baking soda.
Beat in eggs and vanilla till combined.
Beat in as much of the flour as possible. Stir in remaining flour. Add chocolate chips and nuts, if desired.
Drop by rounded teaspoons 2 inches apart on ungreased cookie sheet.
Bake at 375 for 8-10 minutes. Cool on wire rack.