1 cup butter
1 cup vegetable oil
1 cup white sugar
1 cup packed brown sugar
2 eggs
1 teaspoon vanilla
4 1/2 cups flour
2 teaspoons baking soda
1 teaspoon cream of tartar
1 teaspoon salt
2 cups semisweet chocolate chips
Directions:
Preheat the oven to 350 degrees
In a large bowl, cream together the butter, oil, and sugars until smooth. Beat in the eggs and vanilla. Combine the flour, baking soda, cream of tartar and salt; stir into the creamed mixture. Mix in the choc chips. Drop by rounded teaspoons onto stone or ungreased cookie sheets.
Back for 10 minutes. Allow cookies to cool on the stone/baking sheet for a couple of minutes before transferring to wire racks to cool completely.