• Add gochujang, onion, garlic, ginger, soy sauce, sugar, mirin, and sesame oil in a large bowl. Mix with a spoon until combined. Add chicken. Mix thoroughly, making sure each chicken piece is coated with sauce. Cover and marinate for at least 30 minutes but preferably overnight.
• NOTE: depending on thickness, the chicken may require more cooking. Check for doneness before serving.

BBQ Grill:

• NOTE: when grilling on the BBQ, add an additional 1 Tbsp oil (any neutral kind works) into the marinade. This will help with sticking.
• Heat grill on high heat and oil the grates very well.
• When the grill is fully heated, lower the heat to medium. Grill the chicken thighs, turning as necessary, until browned and cooked through. There should be crispy charred edges but watch carefully so it doesn't burn too much. Discard remaining marinade ingredients.
• Transfer chicken to a platter. Optional: garnish with chopped green onion and/or cilantro and a sprinkle of sesame seeds.  Enjoy!

Non-Stick Skillet:

• Heat a non-stick skillet to medium heat. When the skillet is fully heated, add 1 Tbsp oil (any neutral kind works). Gently slide chicken thighs into the oil, being careful as the oil will sputter and pop.
• NOTE: Arrange the chicken in the skillet evenly in one layer, barely touching each other with a little space in between. Depending on the size of the skillet, you may need to cook the chicken in several batches.
• Cover and lower heat to medium low until chicken looks firm and cooked on the edges, about 6-8 minutes. Uncover and cook on the other side, adding more oil if needed, for another 6-8 minutes. Turn and flip as necessary until browned and cooked through. There should be crispy charred edges but watch carefully so it doesn't burn too much.
• Transfer chicken to a platter. Optional: garnish with chopped green onion and/or cilantro and a sprinkle of sesame seeds.  Enjoy immediately!

Instant Pot :

• Put chicken and all of the marinade into the Instant Pot. Spread chicken evenly into one layer. Make sure not to mound chicken in the middle, as this will lead to uneven cooking.
• Cover and lock the lid in place. Cook on Manual function (high pressure) for 8 minutes. When the timer beeps, allow the pressure to release naturally for 10 minutes. Then, release the rest of the pressure manually.
• Transfer chicken to a platter and drizzle generously with sauce. You can shred the chicken or serve as whole thighs. Garnish with chopped green onion and/or cilantro and a sprinkle of sesame seeds. Serve with additional sauce at the table.

Sheet Pan:

• Position oven rack so that it's on the top most rack, about 3-4-inches from the heat source.  Preheat oven to BROIL.   Let the oven heat for at least 10 minutes.  
• Line a sheet pan with aluminum foil for easy clean up. Add chicken thighs to the sheet pan in a single layer.  They should all fit comfortably with some space in between.  Broil until partially cooked with little charred spots on the top, about 5-6 minutes, depending on thickness
• Flip the chicken.  Broil until completely cooked with little charred spots on the top, another 5-6 minutes, depending on thicknessMake sure to watch the chicken carefully - the sauce burns easily.  
• Transfer chicken to a platter. Optional: garnish with chopped green onion and/or cilantro and a sprinkle of sesame seeds.  Enjoy immediately!

Air Fryer:

• Preheat the Air Fryer at 400F for 5 min.
• When the Air Fryer has finished preheating, add a piece of parchment paper to the basket. It should fit the bottom of the basket and go up the sides a little. Make sure it doesn't touch the heating element at the top! Or it will catch on fire!
• Add 2-3 chicken thighs to the parchment paper, evenly spaced apart. Cook at 400F for 5 minutes. Flip thighs. Cook at 400F for another 5 minutes until cooked through with crispy, charred bits. Flip thighs again, to the first side that was cooked. Cook at 400F for 2 minutes for that crispy, charred BBQ flavor.
• Transfer chicken to a platter. Optional: garnish with chopped green onion and/or cilantro and a sprinkle of sesame seeds.  Enjoy immediately!