1 c. butter
1 c. sugar
1/2 c. brown sugar
1 egg
1 tsp. vanilla
2 c. flour
1 tsp. cream of tartar
2 tsp. baking soda
2 c. (12 oz.) chocolate chips

Cream softened butter and sugars together. Add egg and vanilla; beat well. Add dry ingredients and chips; mix thoroughly. Dough will be soft. Drop on non-stick cookie sheet. Bake at 325 degrees for 8-10 minutes. Makes 4 dozen large chewy cookies.