Grate the potatoes into a large bowl and sprinkle them with salt.
Using your hands, press the potato together and squeeze out as much water as you can.
Add the egg, finely chopped green onion, and Parmesan cheese to the potato.
Shape 4-5 cm (1 ½-2 inches) flattened balls and place them either in the airfryer or in a baking pan lined with parchment paper.
Bake for 10-15 minutes at 180ºC/356°F on each side, 20-30 minutes in total, and flip the potato balls after 10 minutes. They are ready when they are golden on both sides with brown edges.
Enjoy them with your favorite sauce and a fresh salad.