Cut into the thick parts of the chicken and butterfly to even the thickness. Coat with shio-koji, put the chicken in a resealable plastic bag, then let it sit in the refrigerator overnight.
Remove from the refrigerator 30 minutes (1 hour in wintertime) before cooking. Microwave for 18-20 minutes. You could also grill it.
If using an oven, bake for 18-20 minutes at 200°C.
If pan frying, cook it on parchment paper or aluminum foil, since it burns easily. First fry the skin side down, cook it to a crisp, then turn over the chicken.
Story Behind this Recipe
I'm really into using shio-koji.
By cooking this on a grill or in the oven, it doesn't burn easily, and turns out tender. Since shio-koji burns easily, I recommend wiping it off when pan frying. Layer the pan with aluminum foil or parchment paper, then pan fry over low heat.