In a large bowl, cream together sugar,
butter, and oil. Stir in the eggs and vanilla. Combine the flour,
baking soda, salt and cream of tartar; stir into the creamed
mixture. Mix in the pecans. Roll the dough into balls the size of
walnuts. Place balls onto ungreased sheet. Press each ball down
with the bottom of a glass dipped in sugar. (Find a glass with a
decorative bottom to give cookies a pattern.).