1. Preheat oven to 300 degrees Fahrenheit. Blend sugars and margarine until grainy paste is formed. Add eggs and vanilla extract and beat until smooth.
2. Drop by rounded tablespoonfuls onto ungreased cookie sheets, two inches apart. Bake for 16 to 20 minutes. Transfer cookies to a cool, flat surface to cool.
3. Add dry ingredients and chocolates; blend at low speed until just combined. Do not over-mix.
Tips:
You can use black and white chocolate chips instead of chopped chocolate bars.