In a small saucepan, add the milk and heavy cream and on medium heat, bring to a simmer. Once it begins to simmer, reduce to low. Add the sweetener and stir into it, until it dissolves.
While the liquids are simmering, whisk the egg yolks. Once the sugar has dissolved, stir through the yolks. Add the vanilla extract and nutmeg, and simmer until desired thickness.
Remove from the heat and pour into 4 mugs, or allow it to cool completely, before refrigerating.
Notes
TO STORE: As the eggnog contains dairy, you must always leave it chilled. Keep it stored in the refrigerator for up to 2 weeks.TO SERVE WARM: Add eggnog to a small saucepan and on low heat, bring to a simmer. Once it begins to simmer, stir slowly. If needed, add extra milk or cream to your desired texture. Remove from the heat, pour into mugs, and add whipped cream and extra nutmeg. TO SERVE CHILLED: Remove from the refrigerator and stir thoroughly, as it will have thickened up. Add extra milk or cream if you prefer a thinner texture. Pour into glasses and top with whipped cream.