Make the donut batter: Add cider, eggs, maple syrup and vanilla to a medium bowl and whisk together to combine. To the bowl, add the almond flour, coconut flour, cinnamon, baking soda, baking powder, nutmeg and salt. Whisk until the batter is fully combine with no lumps.
Drop a tablespoon of batter into each hole (or if using a donut pan divide the batter to make 6 donuts).
Bake in preheated oven for 12-15 minutes until a toothpick comes out clean. Remove the donuts from the pan and let them cool for 10 minutes on a baking rack.
Dip donut holes into butter followed by dipping them into the cinnamon sugar.
Serve immediately or keep covered for up to 1 day at room temperature.
Alternatively, you can bake these in a mini muffin pan and turn them into apple cider mini muffins. Line the muffin tin with parchment or silicone liners, and once cooked you can coat the top in the butter / sugar mixture.