Steps

1. Lightly score the thicker parts of the chicken thighs with scissors. (This is the key!) Over-scoring will cause the chicken to lose its juiciness, so just score enough to help it lay flat.
   🕒 01:30
2. Sprinkle salt to taste on both sides of the chicken thighs.
   🕒 02:02
3. Place 2 tbsp of olive oil in a cold frying pan, then add the chicken thighs skin-side down, spreading the skin out. (This is the key!) Spreading the skin out and tucking it around the meat will help it become extra crispy.
   🕒 02:30
4. Turn the heat to medium-low and cook the skin side only for about 10 minutes. (This is the key!) Starting from a cold pan prevents shrinkage and allows the skin to crisp up gradually. Avoid moving the chicken too much while it's cooking.
   🕒 03:16
5. If any part of the skin seems to be drying out while cooking, add a little more oil as needed to ensure even browning. (This is the key!) Adding oil helps achieve a beautiful, golden brown color all over.
   🕒 04:57
6. Move the chicken to a cooler part of the pan (a 'side change') and use the sides of the pan to evenly crisp the entire skin. (This is the key!) Cook until the skin is a deep brown color. If the skin isn't crispy enough, it won't achieve the desired texture.
   🕒 05:36
7. Once the skin is golden brown and crispy, flip the chicken over.
   🕒 06:39
8. Wipe away any excess oil from the pan and lower the heat. Cook the meat side for about 3 minutes without moving it. (This is the key!) Aim for 80% skin side and 20% meat side cooking. Overcooking the meat will make it tough, so cook it quickly. Avoid steaming as it will reduce crispiness.
   🕒 07:00
9. Remove the cooked chicken from the pan and let it rest, allowing residual heat to finish cooking.
   🕒 07:55
10. Lightly wipe out any excess oil from the pan used to cook the chicken, then add 1/4 finely chopped onion and sauté. (This is the key!) Using the same pan preserves the chicken's delicious flavors, adding depth to the sauce.
    🕒 08:16
11. Once the onions are sautéed, add 2 tbsp of Mirin (Sweet Rice Wine), 1 tsp of sugar, 2 tbsp of soy sauce, 2 tbsp of water, and 1 tbsp of Cooking Sake (Rice Wine) and let it simmer. (This is the key!) Scrape up the browned bits of chicken from the bottom of the pan while simmering to concentrate the sauce's flavor.
    🕒 08:51
12. Turn off the heat once the sauce has slightly thickened.
    🕒 09:22
13. Place the rested chicken steak on a plate, generously drizzle with the Japanese-style onion sauce, and sprinkle with pepper to taste if desired.
    🕒 09:39