Whisk together gluten-free flour, baking powder, baking soda, sea salt, and half of the pumpkin spice. This ensures the spices and leavening agents are evenly distributed.
In another bowl, mix melted butter, egg, maple syrup, apple cider, and applesauce until smooth. This creates a rich, flavorful base for your donuts.
Slowly combine dry ingredients with wet ingredients, stirring until just incorporated. Overmixing can make donuts tough. Transfer batter into a bag, snip a corner, and fill molds ¾ full.
Air fry at 375°F for 10-12 minutes. Donuts are ready when a toothpick comes out clean. Let them cool slightly before adding toppings.
Melt 1-2 tablespoons butter and combine 4 tablespoons sugar with 1 teaspoon pumpkin spice. Brush donuts with butter and roll in sugar mixture for a sweet, spiced finish.