Stir together sugar, butter and evaporated milk in an electric skillet. Set thermostat at 250 degrees F. Boil, stirring constantly, for five minutes. Turn off pan. Stir in marshmallows, PB, and vanilla, until blended completely. Before it gets too cool, pour into a well-buttered 8-inch square pan. Cool. Cut into 16 squares.
Not a NESTLÉ®-tested recipe.