Preheat oven to 350º F.

Combine margarine, oil and sugars in a large mixing bowl; beat until light and fluffy. Add eggs, one at a time, beating well after each addition. Add vanilla, baking soda, salt and cream of tartar. Beat until well mixed. Add flour and stir until well mixed. Shape dough into 1-inch balls; place on ungreased cookie sheets. Flatten with the bottom of a glass dipped in sugar. Bake for 10 to 12 minutes or until lightly browned. Remove from cookie sheet and cool on wire racks. Yield: 8 dozen cookies.

Note: If these are made around Christmas, top with red and/or green sprinkles before cooking.