Preheat oven to 350°. In a large bowl, beat butter, sugars and oil until blended. Beat in eggs and extract. Combine flour, baking soda and cream of tartar; stir into butter mixture (dough will be stiff).
Roll into 1-in. balls; place 2 in. apart on ungreased baking sheets. Press with bottom of a glass dipped in water, then in sugar. Bake 10 minutes or until edges are lightly browned.
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