In a large mixing bowl, combine marshmallow cream, white chocolate morsels and maple extract. Set aside. (I put this in my electric mixing bowl with whisk attachment). In a large saucepan, combine sugar, heavy cream, butter and salt. Heat over medium high heat and bring to a boil, stirring constantly. Once boiling (a good rolling boil), continue boiling over medium high heat for 5 minutes (still stirring). After 5 minutes, remove from heat and pour over the marshmallow cream, white chocolate morsels and maple extract. Blend mixture for about 1-2 minutes until smooth (and white chocolate is melted). Fold in chopped walnuts. Pour into a parchment paper lined 8inch baking dish. Refrigerate 4 hours or overnight. Cut into bite sized pieces and store in an airtight container in the refrigerator for up to two weeks. ENJOY.