01 - Heat 2 inches of vegetable oil in a heavy-bottomed pot or deep skillet to 350°F.
02 - Separate biscuit dough into 8 rounds. Flatten each round and cut a 1-inch hole in the center using a round cutter or bottle cap.
03 - Mix pumpkin purée with pumpkin pie spice. Spread thin layer between two biscuit rounds, press edges firmly to seal, and recut center hole if needed.
04 - Fry donuts in batches for 1-2 minutes per side until golden brown and puffed. Remove with slotted spoon and drain on paper towels.
05 - Combine granulated sugar and cinnamon in shallow bowl. Toss warm donuts in mixture to coat evenly.
06 - Whisk powdered sugar, milk, vanilla extract, and pumpkin pie spice until smooth. Drizzle over cooled donuts.