In a glass measuring cup, combine 2.5 cups of eggnog with ½ cup of heavy whipping cream. Stir gently until well blended.

In a medium saucepan, whisk together ⅔ cup of granulated sugar, 4 tablespoons of cornstarch, ¼ teaspoon of salt, and ½ teaspoon of ground nutmeg until evenly mixed.

Crack 4 large egg yolks into the saucepan with the dry ingredients. Whisk vigorously until smooth.

Gradually pour the eggnog mixture into the egg yolk mixture while continuously whisking.

Place the saucepan over medium heat, stirring constantly until the mixture thickens and begins to bubble.

Once thickened, remove from heat and stir in 1 teaspoon of rum extract and 3 tablespoons of unsalted butter.

Strain the pudding through a fine mesh sieve into a clean bowl to ensure a silky texture.

Cover the surface with plastic wrap and chill in the refrigerator for at least 4 hours or overnight.

Once chilled, scoop the pudding into serving dishes. Garnish with whipped cream, grated nutmeg, and sugared cranberries.