Tempura String Beans with Dipping Sauce

Heat oil in a fryer to 340 degrees F.

In a large bowl beat the egg with the seltzer water until thoroughly combined. Quickly stir in the rice flour and the cake flour using as few strokes as possible to combine. It's acceptable if there are still a few lumps in the batter. Refrigerate the batter for 30 minutes.

Place the all-purpose flour in a medium bowl and set aside as the tempura batter chills.

Working in batches, quickly dip the green beans in the all-purpose flour , shaking off any excess, then roll in the tempura batter, allowing the excess to drain off, and transfer to the hot cooking oil using tongs. Cook until crisp and light golden brown, about 1 1/2 to 2 minutes. Using a slotted spoon, transfer to a paper towel-lined plate to drain. Serve immediately with the dipping sauce.

Combine water, kombu, and bonito flakes and bring to a boil. Simmer for 20 minutes and strain into a clean saucepan . And remainder of ingredients and bring to a boil over medium heat. Remove from the heat and let cool to room temperature before serving.