In a small bowl, whisk egg together with onion; stir into potatoes. Sprinkle in the flour, salt & pepper, mixing to form a dough. Turn dough onto floured surface & knead for about a minute. Dough should be fairly soft. Roll dough into a long noodle. Divide into 5 even pieces, cut each piece into eights, then pinch each piece in half giving you 80 noodles.