Heat oven to 350°F. Line 12 regular size muffin cups with paper baking cups.
In the bowl of your stand mixer with the paddle attached, combine flour, sugar, nutmeg, baking powder, baking soda, and salt.
With the mixer running on medium speed, add about a tablespoon at a time of softened butter. Continue to mix until the dry mixture is coated with the butter.
Mix together eggs and eggnog in a measuring cup with a spout. With the stand mixer running on low speed, add just enough of the liquid mixture (shouldn't be more than half) to the flour to barely moisten the batter. Increase speed to medium and mix until light and fluffy, about 2 minutes. Scrape bowl, add remaining liquid, and mix on low speed until well combined, scraping as necessary.
Bake 25 to 28 minutes or until tops of cupcakes spring back when touched lightly in center and toothpick inserted in center comes out clean. Remove from oven; place on cooling rack. Cool completely, about 45 minutes.
Top with eggnog frosting, candied hazelnuts, and more freshly grated nutmeg