PRAWN TEMPURA

2 cups cake flour
2 cups cornstarch
2 cups ice cold water
½ tsp. iodized salt
1 tsp. sugar
4 tsps. baking powder

Sauce:

1 cup Kikkoman soy sauce
1 cup water
Splash of mirin
Sugar, as needed
Grated ginger
Grated daikon (radish)