Preheat oven to 425° F. Place paper liners in a muffin tin and set aside.
In a large bowl, whisk together flour, baking powder, salt, cinnamon and nutmeg. Set aside.
In a medium bowl, whisk together egg and sugar until combined, about 30 seconds. Then add buttermilk, melted butter and vanilla. Whisk until pale yellow, about another 30 seconds.
Add the wet ingredients to the dry ingredients and whisk just until combined. Avoid over-mixing. Stir in chocolate chips with a spatula or wooden spoon.
Divide batter among paper-lined muffin tin, filling each cup about three-quarters full. Sprinkle additional sugar on top if desired. Bake at 425° F for 5 minutes, then reduce temperature to 375° F and bake for an additional 10-12 minutes or until the muffin tops are light golden brown and a toothpick inserted in the center comes out with little to no crumbs.
Allow muffins to cool in the pan for 5 to 10 minutes before removing and serving.