Preheat oven to 325°F (165°C). Lightly grease donut pan. Mix all dry ingredients flour, sugar, baking powder, baking soda, nutmeg, and cinnamon. Mix buttermilk, eggs, and melted butter in a separate medium bowl, and stir into the dry ingredients.
Fill each donut cup approximately 3/4 full.
Bake 10-12 minutes in the oven, until donuts spring back when touched. Allow to cool slightly before removing from pan.