Cut the chicken thighs into bite-sized pieces.

In a medium glass bowl, combine gochujang, soy sauce, wine, brown sugar, corn syrup, sesame oil, minced garlic, gochugaru, black pepper, and ginger powder.

Mix the marinade ingredients well.

Place the sliced chicken thighs and green onion bottoms in the marinade. Toss to coat the chicken thoroughly, pressing it into the bowl.

Top with sliced onion.

Marinate in the refrigerator for 2-6 hours.

Heat 2 tablespoons of oil in a cast iron skillet or wok over medium-high heat.

Remove most of the onions from the marinade, squeezing out excess marinade.

Add the onions to the skillet and cook for 3-5 minutes, until softened and slightly caramelized.

Drain the remaining marinade from the chicken and green onions (into the sink). Add the chicken and green onions to the skillet with the onions.

Cook on medium-high heat, stirring occasionally, until the chicken is cooked through and slightly caramelized.