Whisk together wet pancake ingredients and sugar until well combined and smooth
Whisk in baking powder, salt, and baking soda until evenly incorporated.
Whisk in flour and nutmeg. Let the batter stand for about 15 minutes. (This is a good time to preheat a cooking pan over medium heat.)
Cook pancakes in the preheated pan for a couple of minutes on each side. Check the pancakes by pressing lightly in the center, if it's firm the pancakes are done.
Eggnog Sauce:
In a small sauce pot, over medium heat, start melting butter.
Once butter is melted, add rum and let it simmer for a minute.
Add eggnog and nutmeg and whisk well. Let it heat through.
Mix cornstarch with a tablespoon or two or cold eggnog and whisk the mixture into the sauce pot.
Cook, stirring, until the mixture starts to simmer and thickens. Take off heat.
Top pancakes with some sauce. You can dust pancakes with a little nutmeg on top as well.