Cream butter and oil; gradually add sugar, beating at medium speed of electric mixer. Add egg and vanilla, mixing well. Combine flour, soda, salt and cream of tartar; gradually add to creamed mixture, mixing well. Stir in oats and remaining ingtedients. Drop dough by teaspoonsful onto greased cookie sheets. Bake at 375 degrees for 10-12 minutes. Cool on wire rack. Makes about 8 dozen.