1. Whisk GF flour, baking powder, baking soda, salt, cream of tartar, ground cinnamon, nutmeg, and sugar.
2. Create a well in the center of the flour mixture, and add the butter, eggs, and cider, and mix to combine.
3. Pipe into donut pan. Bake.
4. Remove donuts from the doughnut pan and roll them in the cinnamon sugar until they are well-coated on all sides.