Remove the shells from the prawns (shrimp), leaving the tails intact.
Remove the heads and any tentacles.
To make the batter, beat all of the ingredients together in a shallow bowl with a whisk or wooden spoon until they are thoroughly blended.
Set the bowl aside.
Fill a large deep-frying pan one-third full with oil and heat it until it is hot.
Dip the prawns (shrimp) first in the batter, coating thoroughly but shaking off any excess, then carefully lower them into the oil, a few at a time.
Deep-fry for 2 to 3 minutes, or until the prawns (shrimp) are golden brown.
Remove from the oil and drain on kitchen towels.
Keep hot while you cook the remaining prawns (shrimp) in the same way.
To make the dipping sauce, combine the soy sauce and spring onions (scallions) and pour into small, individual bowls.