In a medium saucepan, combine 6 tablespoons of granulated sugar with 2 tablespoons of cornstarch. In a separate bowl, whisk together the milk and egg until fully blended. Gradually add the milk mixture to the sugar and cornstarch in the saucepan, whisking constantly to prevent lumps.

Place the saucepan over medium heat and continue whisking the mixture until it reaches a boil. Once boiling, cook for an additional 1 minute, stirring continuously, until the mixture thickens. Remove from heat.

In a small bowl, combine the canned pumpkin, vanilla extract, ground cinnamon, salt, and ground nutmeg. Gradually add this pumpkin mixture into the warm milk base, whisking constantly to ensure a smooth texture.

Return the saucepan to low heat and cook the combined mixture for approximately 3 minutes, stirring constantly, until the pudding is thoroughly heated. Be cautious not to allow the mixture to boil. Remove from heat once heated through.

Evenly divide the pudding among four individual serving bowls. Cover the surface of each pudding with plastic wrap to prevent a skin from forming. Refrigerate until thoroughly chilled.

Line a baking sheet with foil and lightly coat with cooking spray. In a small nonstick skillet, combine the remaining 2 tablespoons of sugar, chopped walnuts, and a dash of salt. Cook over medium-low heat, stirring frequently, until the sugar dissolves and coats the walnuts with a golden caramel glaze. Transfer the candied walnuts to the prepared baking sheet and allow them to cool completely. Once cooled, coarsely chop them.

In a mixing bowl, beat the heavy whipping cream with an electric mixer on high speed until stiff peaks form.

Top each serving of chilled pudding with approximately 2 tablespoons of freshly whipped cream and garnish with about 1 tablespoon of candied walnuts.