Coconut Flour: I use Bob's Red Mill Coconut Flour - order here.
Nutmeg Icing Notes:
I experimented using a low carb sugar like Lakanto in the icing, and it just crystallized after the icing cooled on the donuts, so if you are going to use a sugar alcohol I recommend using a "powdered" one, and expecting it to be a little grainy. Or you can try using a little stevia instead. Liquid maple syrup also works, but it will seem like it's not mixing in with the oil very well, so as soon as you heat then cool the icing to where it's just barely liquid and spreadable, stir it again well, apply to donuts, and when it cools it will form a nice glaze.