Dough consistency: After chilling, the dough should be soft but firm enough to roll and cut. If it is excessively sticky, add flour 1 tablespoon at a time while rolling, using no more than needed.
Substitutions: Full-fat plain Greek yogurt may replace the sour cream. Apple juice may replace the cider, though the apple flavor will be milder. Any neutral high-heat frying oil may be used.
Serving suggestions: Pair with coffee, black tea, or warm apple cider. For dessert, serve with caramel sauce, whipped cream, or vanilla ice cream.
Storage: Keep completely cooled donuts in a loosely covered container at room temperature for up to 2 days. Reheat in a 300°F oven for 5 to 7 minutes.
Freezing: Freeze cooled donuts before adding cinnamonsugar. Store airtight for up to 2 months. Thaw at room temperature, warm briefly in the oven, and coat with fresh cinnamonsugar.