Combine egg yolks and sugar substitute in a mixing bowl, whisk until pale yellow and fluffy. Set aside.

Measure heavy cream, almond milk, nutmeg, and salt into a pot. Cook over medium heat until it just starts to simmer, then turn the heat down to low.

Slowly pour a half cup or so of the hot mixture into the egg mixture, while whisking it. Once smooth, repeat 2 more times.

Pour egg mixture into the pot of cream mixture, whisking well to combine.

Turn heat back to medium, continue to cook - whisking constantly - until mixture starts to thicken, and/or reaches 165F. (Note: It will thicken more as it cools, so don’t let it get too thick!)

Remove from heat, allow to cool for 10 minutes.

Add vanilla extract (and alcohol, if you’re using it), whisk well to combine.

Chill for at least 4 hours before serving.