Prep the chicken. Thinly slice chicken thighs into bite-size strips. Pat dry with paper towels for better browning.
Make the bulgogi marinade. In a bowl, mix soy sauce, brown sugar, rice vinegar, sesame oil, garlic, ginger, and gochujang.
Add chicken and toss to coat. Let sit 10 minutes while you prep the corn.
Start the corn. In a large skillet over medium heat, melt butter. Add garlic and cook 30 seconds until fragrant.
Stir in corn, a pinch of salt, and black pepper. Cook 3–4 minutes (a bit longer if frozen) until hot and slightly toasty at the edges.
Add heat and creaminess. Sprinkle in gochugaru. Stir in mayo or cream if using.
Taste and adjust salt. Transfer to a bowl and keep warm.
Sear the chicken. Wipe out the skillet and heat neutral oil over medium-high until shimmering. Spread chicken in an even layer (work in batches to avoid crowding).
Cook 3–4 minutes per side until caramelized and cooked through.
Reduce and glaze. Pour any remaining marinade into the pan during the last minute to thicken and coat the chicken. Toss with sliced green onions.
Serve. Plate chicken over rice or in lettuce leaves. Add a heap of spicy garlic butter corn on the side.
Finish with sesame seeds, extra green onions, and a squeeze of lime if you like.