Heat the cider in a small saucepan and bring to a simmer. Reduce heat and simmer until the cider has reduced to ½ cup. Set aside to cool.
Preheat the oven to 400 degrees and spray a 9 wells of 2 regular doughnut pans with gluten-free cooking spray. (Tip: if you need to bake the doughnuts in more than one batch, make sure to re-spray the pan with gluten-free cooking spray)
Add the flour blend, almond flour, xanthan gum if using, baking powder, baking soda, cinnamon, salt, nutmeg and cloves to a large bowl and whisk to combine.
Add the sugar, eggs, buttermilk, vanilla and reduced cider and whisk until smooth.
Pour the mixture into a large zip-top bag and snip about ½ inch off one corner. Carefully pipe mixture into your prepared doughnut pan, filling each well about 3/4 full.
Bake the doughnuts until they spring back when gently touched, about 8 minutes for the minis, 10 minutes for the larger ones.
Dip or brush the doughnuts with the melted butter just as soon as they are cool enough to handle and gently toss with the cinnamon/sugar mixture.