Sugar Cookies

1 C butter, softened
1 C vegetable oil
1 C sugar
1 C confectioners' sugar
2 large eggs
1 tsp vanilla extract
4 1/2 C all-purpose flour
1 tsp baking soda
1 tsp cream of tartar

In a large bowl, beat the butter, oil, and sugars. Beat in eggs until well blended. Beat in vanilla. Combine the flour, baking soda, and cream of tartar; gradually add to creamed mixture.  Drop by small teaspoonfuls onto ungreased baking sheets. Bake at 375 degrees until lightly browned, 8-10 minutes. Remove to wire racks to cool.