Take the chicken out of the fridge and temper at room temp for 30 to 1 hour. Heat the oven to 400°F.
Make a marinade by mixing together the gochujang, 2 tablespoons oil, and soy sauce.
Rub or brush the marinade all over the chicken – you will have some left over. Place the chicken in a roasting dish.
Add the last 2 tablespoons of oil to the marinade. Toss the potatoes in the marinade, then arrange in a single layer around the chicken in the roasting dish. Cut out a tiny piece of foil (large enough just to cover the chicken breast) and place it on top – this will prevent it from browning too much.
Roast the chicken on the lowest rack for about 1 hour to 1 hour and 15 minutes or until the thickest part of the chicken thigh reads 155ºF/160ºF (the chicken will cook another 10 degrees while resting, use the higher temperature if you don’t want to see any pink in the chicken) and the potatoes are fork tender. Remove the foil for the last 15 minutes of cooking and give the potatoes a toss.
When the chicken is done, baste with the honey and rest the chicken for 5-10 minutes before digging in. Finish with green onions and cilantro, if desired.