1/2 c Butter; room temperature (1
1/2 c Vegetable oil
1/2 c Sugar
1/2 c Powdered sugar
1 ts Vanilla extract
2 1/4 c All purpose flour
1/2 ts Baking soda
1/2 ts Cream of tartar
1/2 ts Salt
Using electric mixer, beat butter, oil, 1/2 cup sugar and 1/2 cup powdered
sugar in large bowl until well blended. Mix in egg and vanilla. Sift flour,
baking soda, cream of tartar and salt over and mix in. Cover mixture and
chill until firm, about 30 minutes or up to 1 day.
Preheat oven to 350F. Butter 2 heavy large baking sheets. Roll 1 tablespoon
dough into ball. Place on prepared sheet. Repeat with remaining dough,
spacing balls evenly on sheets. Dip flat-bottomed glass into water to
moisten, then dip into sugar and press dough to 1/4-inch-thick round.
Repeat with remaining dough balls, dipping bottom of glass into sugar
before pressing each.
Bake cookies until light brown, about 15 minutes. Transfer cookies to racks
and cool completely.
Makes About 36.