Pat 350 g boneless chicken thigh(s) dry with a paper towel and pierce both sides thoroughly with a fork.
Cut into 30-40g (1-1.4oz) pieces and place them in a bowl. Sprinkle with ½ tsp salt and massage until all the pieces are evenly seasoned.
Add 1 ½ tbsp ginger root, 1 tbsp garlic, ½ tbsp apple(s), 1 tbsp sake, 1 tsp Japanese mayonnaise, 1 tsp sesame oil, 1 tsp shiro dashi, ½ tsp Chinese-style chicken bouillon powder and ⅛ tsp white pepper powder to the bowl and mix thoroughly.
Next, add 1 tbsp all-purpose flour to the bowl and 1 tbsp tapioca starch, mix until the chicken is evenly coated.
Cover the bowl and rest the chicken in the fridge for at least 30 minutes, preferably 1 hour.
Once the chicken has rested, preheat the oil to 160 °C (320 °F). While you wait, add 4 tbsp potato starch to a plate and sprinkle with 2 tsp water. Mix with chopsticks or fork to make clumps of starch for the hailstone effect. Remove the chicken from the fridge and lightly coat each piece with the clumpy starch mixture.
Deep fry the chicken for 3 minutes. Do not touch for the first minute or so. After that, turn occasionally to promote even cooking.
Remove the chicken from the oil and rest on a wire rack for 3 minutes. (It will continue to cook in the residual heat.) While the chicken is resting, increase the heat of the oil to 180 °C (356 °F) - 190 °C (374 °F).
Once 3 minutes of resting time is up, deep fry the chicken again for 30 seconds to 1 minute or until golden brown all over.
Transfer to a wire rack to drain the excess oil.
Serve up and enjoy with a slice of lemon!