A traditional Japanese tempura batter is made from equal parts white flour and ice water, plus one egg for each cup of water. Some recipes also include baking soda. The batter is used to coat vegetables and seafood before deep-frying.
A good tempura batter will be as light and crispy as possible when cooked, and not too oily or thick. To achieve this, the batter must be thin and very cold, and the battered foods are cooked immediately in very hot oil. Tempura is usually made from vegetables or seafood.
Popular tempura foods include shrimp, green beans, sweet potato, shiitake mushrooms and lotus root. Almost any vegetable can be made into tempura, but not all vegetables work well with this method. For example, broccoli florets tend to be improperly cooked in tempura, and tempura battered carrots often taste unpleasant.
To make a simple tempura batter, beat 1 egg in a bowl. Add 1 cup of ice water and blend lightly. Then, add 1 cup of flour all at once. Mix the flour into the egg and water with a fork until it is just combined, but still quite lumpy. A lumpy batter results in crispy tempura; if the batter is smooth, it will absorb too much oil during cooking.