In a small sauce pan, boil the apple cider down until it is reduced to 1/4 cup. Allow to cool.

In a large bowl, cream together the butter and sugar until fluffy. Beat in the eggs. Beat in the buttermilk and reduced apple cider.

In a medium bowl, whisk together 3 1/2 cups of the flour, the baking powder and soda, and the cinnamon, nutmeg, cardamom, and salt. Add the dry ingredients to the wet ingredients until combined. The dough will be very sticky.

Transfer the dough to a floured surface and knead, adding in the additional flour (you may not need the full remaining 2 cups), until the dough is no longer sticky. Roll out the dough to 1/2″ thickness, and using a 1″ cutter, cut out the doughnut holes. Re-roll the scraps of dough and continue cutting until there is no dough left.

In an electric fryer or a deep pan, add 3″ of vegetable oil. Fry several doughnut holes at a time, turning occasionally, until they are browned and cooked through. Remove the cooked doughnut holes to a paper towel-lined plate. Immediately coat them in the cinnamon-sugar mixture.