The easiest tempura batter is bought over the counter at the store, but you can make your own as follows: 1 c. cold water, 1 egg, 1 c. flour

Measure flour in a bowl and add COLD water. Stir slightly until flour is lumpy. (Do no mix too well.) Add a cold egg. Stir slightly, but do not mix well. Batter must be cold at all times. Too much mixing or warm batter will make it doughy.