
Preheat your oven to 425F (218C).
If you have time, remove the chicken thighs from the refrigerator 10-15 minutes before cooking. Season both sides with salt. Also season the meat side with garlic powder and black pepper.
Place an ovenproof heavy-bottommed pan over medium heat. Add cooking oil and once the oil is hot, add chicken thighs skin side down in a single layer. Brown for about 3 minutes until the skin starts to turn light golden.
Put the pan into the oven still with the skin side down. Cook for 7-8 minutes until almost cooked through (with internal temperature around 160F).
Take the pan out of the oven and put it back on the stove over medium-high heat. Flip the chicken thighs and sear the meat side for about 30 seconds until the internal temperature reaches 165F. Transfer chicken thighs to clean plates.
Discard the fat in the pan. Place the pan back over medium heat and then carefully add sake. Stir and deglaze the pan for 15-20 seconds. Then add chicken stock and let the liquid come to a simmer. Finally, add butter and soy sauce, stir to combine and continue to simmer to thicken the sauce to your liking. Adjust seasoning to taste.
Serve the chicken thighs with pan sauce, salad or steamed vegetables and rice.