Coat and sear the chicken: Toss the chicken pieces with salt, pepper, and 1 tablespoon cornstarch until lightly coated. Heat the vegetable oil in a large skillet over medium-high heat, then add the chicken in a single layer and sear for 5–6 minutes per side, until golden and cooked through (internal temperature of 165°F). Remove to a plate.

Build the sauce base: In the same skillet, reduce heat to medium and add the gochujang, soy sauce, honey, rice vinegar, sesame oil, garlic, ginger, and water. Whisk together until smooth, scraping up any browned bits left from the chicken.

Simmer until glossy: Let the sauce simmer for 2–3 minutes, until it starts to thicken slightly and smells fragrant rather than sharp. It should coat the back of a spoon lightly at this stage, but don't expect it to be fully thick yet.

Finish with the slurry, not before: Stir the cornstarch slurry, then pour it into the simmering sauce while stirring constantly. Let it bubble for 30–60 seconds, until the sauce turns glossy and visibly thickens. Adding the slurry at the very end instead of simmering cornstarch in from the start is what keeps the glaze clingy and glossy rather than gluey — cornstarch added too early and cooked too long can break down and turn the sauce gummy or start to thin back out.

Return the chicken to the pan: Add the seared chicken back into the skillet and toss to coat every piece in the glaze, cooking for another minute so the sauce clings evenly.

Garnish and serve: Top with sliced green onions and sesame seeds, and serve over rice. If you want a lighter side to balance the richness, our Quick Pickled Cucumber Salad is a natural pairing here.