In a large bowl, whisk together flour, baking powder, salt and nutmeg.
In a medium bowl, whisk together eggs, vanilla and melted butter. Whisk in 2 cups eggnog. Add wet ingredients to dry ingredients and stir until smooth.
If needed, add additional eggnog, a little bit at a time, until batter reaches desired consistency.
Pour batter by 1/4 cupfuls onto a lightly greased, hot griddle. Turn pancakes when bubbles form on top, then cook a minute or two longer, until the second side is golden brown.
Serve pancakes warm, topped with vanilla syrup, whipped cream, and ground nutmeg.
To make syrup: In a medium sauce pan whisk together water, sugar and cornstarch. Bring to a boil. Boil, stirring constantly for 3-5 minutes.
Reduce heat. Stir in butter, salt and vanilla until butter is completely melted. Add heavy cream and simmer a few minutes longer.