1.Make tempura batter: combine egg and soda water in bowl. Add sifted flours at once; mix lightly until just combined. Do not overmix; mixture should be lumpy.
2.Shell and devein prawns; chop prawns and scallops coarsely.
3.Cut carrot and daikon into thin strips.
4.Combine seafood, vegetables, mitsuba and flour in large bowl. Place tempura batter in another large bowl; lightly fold seafood mixture through batter.
5.Heat combined oils in large saucepan; deep-fry tablespoons of seafood mixture, in batches, until golden and cooked through. Drain on absorbent paper.
6.Serve fritters with dipping sauce.
Ready-made tempura dipping sauce is available from most Asian grocers.Note