Mix the sugar milk and corn syrup in heavy 2-quart saucepan Cook stirring constantly over medium heat to a boil mixture will be bubbling all over top Boil and stir another 2 minutes more Take off heat Stir in the chocolate chips until completely melted Cool about 15 minutes
Stir in the pecans and marshmallows Drop by 2 teaspoons onto wax paper
Chill until firm or put in a buttered pan and cut into pieces