Mix in large mixing bowl, butter and sugars.
Add eggs, mix well
Add the flour, cream of tartar, baking soda and salt. Mix well.
Add the oatmeal and both chips. Mix well.
Drop by teaspoon (I use mini scoop) onto parchment lined cookie sheets.
Bake at 400 degrees for 5-6 minutes.
DO NOT overbake, will be hard!