Take the breast meat and remove any fat before cutting into bite-sized pieces.
Add the meat and the ingredients marked with ● into a thick plastic bag and rub together. Leave to chill in the refrigerator for 1 hour.
Add the cake flour and baking powder to a bowl and mix together with a whisk (or simply sift together).
In a separate bowl, combine the beaten egg and water and mix the flour mixture into it in 3 goes with cooking chopsticks. It's better not to over-mix, so don't worry if there are a few lumps remaining.
Coat the chicken in the mixture from step 4 and fry in oil heated to around 180℃. Flip over once during cooking. Please refer to the hints section about this.
Arrange the fried chicken on a plate and you're done. In our house we serve it with a vinegar soy sauce mixture and Japanese mustard.
Story Behind this Recipe
This is the Oita chicken tempura that I have been making for decades. I've changed bits and pieces of the recipe over the years but here's the final version.
I think the recipe is different depending on the family and restaurant.
Try not to over-fry the chicken and take out any burned clumps as you find them.
If you want it to be crispy, fry without coating with egg. If you want a more fluffy coating, then use egg. It's up to you.