Tempura batter is a classic light and crispy batter used in Japanese cooking, to traditionally coat pieces of vegetable and seafood. It is deep-fried and can be served as a starter or main course. Combine the batter mix with 225ml of ice cold water (less for a thicker batter). Replace the ice cold water with carbonated water, for an even lighter batter. Beat with a balloon whisk to remove any lumps. Dip in the vegetables or seafood, let any excess batter drip from the surface and then deep-fry in vegetable oil, until golden brown.