Cream margarine, sugars and oil until well blended. Add eggs and vanilla and mix. Sift 2 cups of flour with soda and cream of tartar and add to egg mixture. Stir in remaining 2 cups of flour. Mix well.
Refrigerate 4 hours or more. Shape dough into walnut-sized balls. Place on well-greased cookie sheet 10 cm apart. Flatten with flat bottomed damp glass dipped in sugar. Bake at 350 degrees 13-14 minutes until delicately browned.