Steps

1. Remove the skin from the chicken breast.
   🕒 00:24
2. Cut the chicken breast into 3 parts along the grain. [This is the secret!] Understanding the direction of the fibers results in a tender texture.
   🕒 00:40
3. Slice the cut chicken breast into 1cm thick pieces, cutting against the grain by laying the knife blade flat.
   🕒 01:05
4. Pierce the cut chicken breast all over with a fork. [This is the secret!] This prevents shrinkage from heat and allows the seasoning to penetrate better.
   🕒 01:50
5. Place the cut chicken breast in a bowl and add 2 tsp sake, 2 tsp soy sauce, 1/2 tsp grated ginger, 1/2 tsp grated garlic, salt and pepper to taste, and 2 tsp sesame oil. Mix well by massaging.
   🕒 02:08
6. Let the massaged chicken breast marinate at room temperature for 20 minutes without refrigerating.
   🕒 02:41
7. Cut the kabosu in half and squeeze out 1 tbsp kabosu juice.
   🕒 02:50
8. In a separate bowl, combine 1 tbsp kabosu juice, 1 tbsp soy sauce, and 1 tbsp vinegar. Mix to create the special seasoned soy sauce.
   🕒 03:05
9. Add oil to a deep fryer and begin heating to 180℃.
   🕒 03:21
10. In another bowl, add 1 tbsp mayonnaise and gradually add cold water while mixing to dissolve. [This is the secret!] Mayonnaise and cold water make the batter crispy.
    🕒 03:26
11. Add 30g cake flour and 30g potato starch to the dissolved mayonnaise mixture. Gently mix with chopsticks in a cross pattern. [This is the secret!] Overmixing will make it gummy, so don't worry about lumps.
    🕒 03:42
12. Add the tempura batter to the marinated chicken breast and mix lightly to coat.
    🕒 03:55
13. Carefully place the chicken breast into the oil heated to 180℃, ensuring the amount of chicken does not exceed 2/3 of the oil surface area. Fry for 2 minutes.
    🕒 04:04
14. Place the fried toriten on a wire rack with a tray underneath to drain the oil.
    🕒 04:24
15. Leave the drained toriten as is for 4 minutes to finish cooking with residual heat. [This is the secret!] Frying at 180℃ for 2 minutes and then resting for 4 minutes with residual heat results in a tender texture.
    🕒 04:30
16. Arrange the drained toriten on a plate. Serve with mustard if desired.
    🕒 04:49