1.Shell and devein prawns; chop finely.
2.Sift flours and soda into medium bowl. Make well in centre; whisk in eggs, water and sauce to make a smooth batter.
3.Stir prawns, wombok and onion into batter.
4.Cook teaspoons of batter, in batches, in large oiled frying pan over medium heat until bubbles appear. Turn pancakes to cook other side. Place on wire rack to cool.
5.Top each pancake with ¼ teaspoon mayonnaise, a drop of tonkatsu and a sprinkling of seaweed. Serve immediately.
Tonkatsu sauce is available ready-made from Asian food stores or you can make your own Use scissors to finely shred the sheets of seaweed.Note