Preheat the oven to 350 degrees F and line a cupcake tin with liners.
Beat together the cake mix, eggnog, eggs, melted butter, nutmeg and cinnamon in a large mixing bowl with a hand held mixer or stand up mixer until combined. Then beat for 2-3 minutes to make sure that the cupcakes are light and fluffy.
Pour the batter into the muffin tins until they are approximately 2/3 of the way full.
Bake for 12-14 minutes or until a toothpick inserted into the center comes out clean.
Move the cupcakes to a wire rack to cool completely.
Make sure that the cupcakes are completely cool before topping with the frosting.
FOR THE FROSTING:
In a large mixing bowl, cream together the butter and shortening until well combined.
Add in half of the powdered sugar and mix until well combined.
Then mix in the eggnog, vanilla extract and nutmeg and mix until smooth.
Then add in the remaining powdered sugar until combined and the frosting is smooth.
Frost the cupcakes with the eggnog buttercream frosting and sprinkle with a little nutmeg (if desired).
Serve and enjoy!
Notes
Refrigerate the leftovers in an airtight container for up to 5 days.