Heat the oven to 350 degrees F. Spray two donut trays with non-stick spray.
In a small sauce pan, reduce the hard cider over medium heat by about half a cup (for about 20 minutes). Meanwhile, melt the butter and set aside to cool.
Whisk together the flour, baking soda, baking powder, salt, spices, and 1 teaspoon of the cinnamon in a large bowl. In a separate measuring cup, whisk together the reduced hard cider, brown sugar, milk, vanilla extract, and single egg until combined. Combine the wet ingredients with the dry ingredients, and stir together with a wooden spoon.
Transfer the dough to the baking trays, and bake in the oven for 10-12 minutes. The donuts are done when you press into the cake and the sponge bounces back immediately. Remove from the oven, let cool in the pan for 5 minutes, and then transfer to a cooling rack.
When the donuts are finished and cool enough to handle, whisk together the granulated sugar with the remaining ¾ teaspoon ground cinnamon. Roll the donuts in the mixture until fully coated. Store the donuts in an airtight container at room temperature, and enjoy within 3-4 days. To make ahead, allow the donuts to cool completely, and then freeze. Thaw in the fridge the evening before you wish to eat the frozen donuts so that they have a chance to thaw.