In a medium saucepan, whisk together 1½ cups of eggnog, ½ cup of granulated sugar, 2 egg yolks, and 1 tablespoon of cornstarch until smooth.

Place the saucepan over medium heat and whisk constantly for about 7-9 minutes until it thickens to a pudding-like consistency.

Once thickened, remove from heat and stir in ¼ teaspoon of ground nutmeg, 1 tablespoon of unsalted butter, ½ teaspoon of vanilla extract, and a pinch of salt.

For an extra-smooth finish, pour the thickened mixture through a fine mesh strainer.

Let the Eggnog Jam cool for 10-15 minutes; then transfer to a clean jar or bowl.