2 sticks butter
1 cup oil
1 cup white sugar
1 cup powdered sugar
2 eggs
2 tsp. vanilla
4 1/4 cups flour
1 tsp. cream of tartar
1 tsp. baking soda
1/3 tsp. salt

Mix together, butter, oil, sugars, eggs, and vanilla. Sift dry ingredients together and add to other ingredients. Refrigerate for 2 hours or more. Roll in small balls, the size of a walnut. Flatten with a glass that is dipped in water then sugar.

Bake for 10 minutes at 350°F.