Preheat the oven to 350 F and prepare a silicone donut panCombine the tigernut flour, coconut flour, and tapioca starch in a large mixing and sift togetherAdd in the maple syrup, pumpkin puree, coconut milk, coconut oil, cinnamon, and baking powder and stir well to combineFor the gelatin egg (sub 1 regular egg if tolerated) place a small pot on the stove with 1/4 cup of water and lightly sprinkle in the 1 tbsp of gelatin. You don't want any clumps. Allow the gelatin to bloom for 2-3 minutes.Turn the stove on low heat to let the gelatin melt. This will take 1-2 minutes. Don't let it burn!Remove the mixture from the stove and use a whisk or immersion blender to vigorously whisk the mixture until it's frothy.Add the gelatin egg (or regular egg) to the pumpkin mixture and stir together immediately.Scoop the mixture into the donut pan (you should have 3 regular sized donuts or 4-5 mini donuts) and spread evenly to prevent breaking.Bake for 35-40 minutes.Remove from the oven and allow to cool for 15-20 minutes in the silicone pan. After slightly cooled, place a cooling rack (or a plate) on top of the donut pan and flip it upside down to remove the donuts. Picking at them or scooping them out with a spoon may break them.Allow the donuts to cool for another 10-15 minutes on the cooling rack.For the optional frosting, whisk together the ingredients vigorously in a small mixing bowl until combined. Spread on the frosting once the donuts are cooled to the touch.