Pour canned milk into a large pot, add sugar and mix well. Cook to a rolling boil and time for eight minutes. Pour hot milk mixture over butter, chocolate chips, vanilla, and peanut butter. Beat until evenly mixed. This sets up quickly so work must be done fast. Pour mixture into a 9 X 13 inch pan prepared with pam. Place uncovered in refrigerator to cool. Cut into squares. Prep time is about 5 minutes, cook time is about 15 minutes, cool down time about 25 minutes. Time need from start to end is about 45 minutes or less.