Instructions:
- Prepare the Cider Reduction: Pour 4 cups of cider into a heavy-bottomed saucepan. Bring to a boil, then reduce heat and simmer until reduced by about 75% (should yield about 1 cup of thick syrup). Cool the syrup completely.
- Combine Dry Ingredients: Whisk together flour, sugar, baking powder, 1 tsp cinnamon, ½ tsp nutmeg, and 1 tsp salt in a large bowl.
- Cut in Butter: Cut the cold butter into the dry ingredients using a pastry blender or fingers until the mixture resembles coarse crumbs.
- Mix Wet Ingredients: In a separate bowl, whisk together the cooled cider reduction, egg, milk, and vanilla.
- Form Dough: Pour the wet mixture into the dry ingredients. Mix gently until just combined; do not overmix. Gather the shaggy dough into a ball, wrap, and chill for 15 minutes.
- Roll and Cut: On a lightly floured surface, roll the dough to about ½-inch thickness. Use donut cutters to punch out donuts and donut holes. Place cutouts on parchment-lined trays.
- Heat Oil: Heat the neutral oil in a Dutch oven or deep frying pot to precisely 350°F (175°C). Monitor the temperature carefully with a thermometer.
- Fry Donuts: Carefully drop 2-3 donuts at a time into the hot oil. Fry for 60-90 seconds per side until deeply golden brown. Remove with a slotted spoon and place on a wire rack set over a baking sheet to drain.
- Make the Glaze: While donuts cool slightly, whisk together the sifted powdered sugar, 3–4 tablespoons of warm cider reduction, ¼ tsp cinnamon, and a pinch of salt until smooth. Adjust cider for desired consistency.
- Glaze and Serve: Dip the top side of each slightly warm donut into the glaze. Allow the glaze to set on the rack before serving immediately.