1 2/3 cups all-purpose flour
1 1/2 cups cornstarch
2 cups club soda
Mix all the ingredients together in a bowl.
To use the batter, heat vegetable oil to 350°F in a deep fryer or heavy-bottomed pot. Dip vegetables, seafood, or anything else you desire into the batter, and deep fry until pale golden brown. Drain the tempura on a wire rack.