Preheat oven to 350 degrees F (180 degrees C). Line a muffin pan with cupcake liners.
In a medium bowl, combine the flour, baking powder, baking soda, salt, and nutmeg with a whisk.
In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and sugar until light in color and fluffy, about 3-4 minutes. Add the vanilla extract and eggnog and mix until well combined.
Beat in the eggs one at a time.
Gradually mix in the dry ingredients until just combined, being careful not to overmix.
Fill the prepared muffin tins with cupcake batter, about 2/3 full.
Bake in the middle of the oven for 20-22 minutes or until a toothpick comes out clean when inserted into the middle of one of the cucpakes. Set aside to cool.
Make the eggnog buttercream according to the recipe. Fill a pastry bag fitted with a piping tip with the eggnog buttercream. Pipe the frosting on each cupcake. Sprinkle the cupcakes with sprinkles or a light dusting of ground nutmeg.