Using the tip of the knife, prick the chicken skin so the fat can render more easily. Thoroughly pat the chicken dry and place it in the plastic bag.
Add the all-purpose miso sauce, remove the air, and zip up the plastic bag.
Rub the chicken well from outside the bag so the miso sauce is distributed evenly. Store in the refrigerator for 24 hours (but no more than that, as the chicken gets salty). Do you plan to freeze them? See below for storing information.
To Cook the Chicken
Take out the chicken from the plastic wrap (I’ll be cooking two), removing the miso sauce as much as possible with your hands (and discard this miso sauce). Using a paper towel, remove the miso as much as possible and make sure the chicken is completely dry. Set aside.
In a large frying pan, add 1 Tbsp oil and distribute evenly. Don’t turn on the heat yet.
Place the chicken skin-side down. Do not crowd the pan, and make sure there is some space in between so the chicken won’t end up being steamed.
Turn on the heat to medium-low to medium heat. Slowly cook the skin so the fat will render. DO NOT TOUCH the chicken for the next 7 minutes, except for occasionally pressing down with a spatula. Do not cover with a lid, but you can use a mesh splatter guard to avoid oil splatter.
Slowly peek to see the skin is nicely browned and the edges of the chicken turn opaque. If so, flip and continue to cook the other side, for about 5 minutes. If not, continue to cook undisturbed for a little longer until well-browned. You can wipe off the oil that is rendered from the skin. Continue to press down occasionally to get the surface nicely seared.
Once both sides are nicely browned, remove from the pan and place the chicken on the cutting board until slightly cool for you to handle. If you have an instant-read thermometer, the safe temperature for chicken 165ºF (74ºC).
To make the Drizzling Sauce, quickly wipe off the oil in the frying pan with a paper towel and add the miso sauce. For 1 chicken thigh, you need 1 Tbsp all-purpose miso sauce and 1 Tbsp water. Bring the sauce to simmer and once thicken, turn off the heat.
Cut into ½-inch strips (as we eat with chopsticks). Serve on a plate or over the steamed rice (in this recipe) and drizzle the sauce over.
Sprinkle sesame seeds and chopped green onion. Serve warm.
You can keep the leftovers in an airtight container and store in the fridge for a month. You can also store uncooked chicken for 2-3 weeks. Make sure to remove miso completely so the chicken doesn't get too salty.