Grease 9×13 baking pan, set aside.

In heavy 2.5 quart saucepan, combine sugar, butter and evaporated milk.  Bring to a full boil while stirring constantly. Continue boiling over medium heat for 5 minutes while stirring.

Remove from heat and stir in chocolate chips. When chips are melted, beat in marshmallow creme, vanilla and walnuts (if using) until fully combined.

Pour into prepared pan and let cool at room temperature.  Cut into squares and enjoy!