In large bowl, beat granulated sugar, powdered sugar and butter with electric mixer on medium speed until light and fluffy.

Beat in oil, vanilla and eggs until well blended.

On low speed, beat in flour, baking soda, cream of tartar and salt until dough forms.

Cover with plastic wrap; refrigerate at least 2 hours or overnight.

Heat oven to 375°F.

Shape dough into 1-inch balls.

On ungreased cookie sheets, place balls 2 inches apart.

Flatten each with bottom of glass dipped in colored sugar.

Bake 5 to 8 minutes or until set but not brown.

Immediately remove from cookie sheets to cooling racks.