In a glass measuring cup, pour together 2 cups of eggnog and 1 cup of heavy whipping cream; set aside.

In a medium saucepan, whisk together 3/4 cup of granulated sugar, 1/4 cup of cornstarch, a pinch of salt, and 1/2 teaspoon of ground nutmeg.

Add 4 egg yolks to the dry ingredients, whisking until smooth.

Slowly pour the eggnog and cream mixture into the saucepan while whisking continuously.

Place the saucepan over medium heat and cook the mixture, stirring constantly until it thickens and begins to boil—about 8 to 10 minutes.

Remove from the heat and stir in 1 teaspoon of rum extract and 2 tablespoons of unsalted butter.

Strain the pudding through a fine mesh sieve into a clean bowl, cover with plastic wrap, and refrigerate for at least 4 hours or overnight.

When ready to serve, scoop the chilled pudding into dishes, topping each with whipped cream, grated nutmeg, and sugared cranberries.