To a 3 ounce package of softened cream cheese, slowly add 1 cup heavy cream, stirring until blended. Stir in 6 marshmallows which have been cut into quarters and 1/4 cup granulated sugar. Chill at least 4 hours. Add 1 teaspoon vanilla. Whip until stiff and then fold in 1/2 cup chopped toasted walnuts. Chill until ready to serve.