Mix in a heavy 2 quart saucepan: sugar, butter, evaporated milk and marshmallow cream. Bring to a bubbling boil over medium heat stirring (preferably with wooden spoon) constantly. When bubbles appear all over top, stir for 8 more minutes. Remove from heat and add the chocolate chips. Stir until completely melted and blended into mixture. Add vanilla and if you want nuts, add them at this time. Pour in lightly buttered 8 or 9-inch square pan. Cool thoroughly and cut into squares. <br><br><br><br>You can use either milk chocolate or semi-sweet chocolate chips. Makes 2 1/4 pounds.