Preheat the oven to 180°C or 350°F and prepare the muffin tin with cupcake liners.
In a bowl mix together the flour, baking powder, salt and nutmeg. Set aside.
Combine together the melted butter, icing sugar, vanilla and eggs.
Start adding some of the flour and mix it in the batter, add half of the eggnog and mix. Alternate between the flour and eggnog, until all the ingredients are combined well together.
With an ice cream scoop or a 1/4 cup, fill in each cupcake liner halfway through.
Bake the cupcakes for about 20 minutes or until a cake tester/toothpick comes out clean.
Remove from pan and let cool completely on wire rack.