1 c. softened butter
1 c. cooking oil
1 c. granulated sugar
1 c. powdered sugar
2 eggs
1 tsp. vanilla
4 1/2 c. flour
1 tsp. baking soda
1 tsp. cream of tartar

Mix first 4 ingredients until fluffy. Add eggs and beat well. Add vanilla. Mix sifted flour and other dry ingredients and add to cream mixture. Chill dough for several hours or overnight. Roll dough in 1" balls and place on ungreased baking sheet giving room to spread. Bake at 350 degrees for 8 or 10 minutes. Dough will keep good in refrigerator for several days if covered tightly.