For the onion rings, cut the onion into 5 mm wide rings and separate them from each other. Place the rings in ice-cold water for 1 hour.
Drain the onion rings well. Mix egg, flour, salt, chili powder and water to make a thick batter. Pour bread crumbs into a soup plate.
Pull the onion rings through the batter first and then roll them in the bread crumbs. Heat oil in a frying pan and fry the onion rings in batches.
Arrange the onion rings and serve.