In a mixing bowl, combine flour, baking powder, salt, egg, and water. Mix well to make a batter.
Dip onion rings into the batter.
Heat cooking oil in a pan or pot. Deep-fry the onion rings in batches. Cook until both sides turn golden brown.
Remove from heat then drain excess oil with tissue paper or wire rack.
Serve while hot and enjoy your crispy fried onion rings!