Preheat the oven to 350°F. Spread the walnuts in a single layer on a baking sheet. Toast for 6-8 minutes then set aside to cool.
Generously butter the bottom and sides of a 9 x 13 inch pan or line with aluminum foil and butter the foil.
In a heavy bottomed saucepan, melt together the granulated sugar, butter, salt, milk and pumpkin puree. Cook over medium heat until the ingredients have melted and the sugar has dissolved.
Using a candy thermometer, continue to cook until soft ball stage approximately 234°F. [around 20 minutes]
Remove from the heat and add the cinnamon chips and vanilla extract. Stir until the chips have melted.
Add the marshmallow cream and toasted walnuts. Work quickly the fudge will begin to set up.
Pour into the buttered pan and spread evenly.
Sprinkle the top with toffee bits and a sprinkle of coarse sea salt. Gently press into the top of the soft fudge.
Allow to sit until cooled to room temperature.
Cut into desired size squares.