Slice and Season: Cut the chicken into bite-sized pieces. In a large bowl, combine the chicken with 2 tbsp cornstarch, ½ tsp salt, and ½ tsp black pepper, ensuring each piece is evenly coated.
Heat Oil: In a large skillet, heat 4 tbsp vegetable oil over medium-high heat.
Sear the Chicken: Add the chicken pieces to the hot skillet in a single layer. Cook for 4-5 minutes on each side until golden brown and cooked through. Avoid overcrowding the pan; cook in batches if necessary.
Remove and Set Aside: Once cooked, transfer the chicken to a plate and cover to keep warm.
Prepare the Sticky Glaze: In the same skillet, melt 2 tbsp unsalted butter over medium heat. Add 8 minced garlic cloves and sauté for about 1-2 minutes until fragrant and slightly golden. Add the red chili flakes.
Add Liquids: Pour in ½ cup honey, 1 cup chicken stock, 2 tbsp rice vinegar, and 2 tbsp light soy sauce. Stir to combine.
Thicken the Sauce: In a small bowl, mix 2 tsp cornstarch with 1 tbsp cold water until smooth.
Combine: Slowly pour the cornstarch slurry a little bit at a time into the skillet, stirring continuously to avoid lumps. Continue to cook the sauce, stirring occasionally, for about 5 minutes, or until it thickens to a sticky glaze consistency.
Combine Chicken and Glaze: Add the cooked chicken back to the skillet, tossing to coat each piece evenly with the sticky glaze. Let the chicken simmer in the sauce for 2-3 minutes, allowing the flavors to meld.
Serve: Transfer the sticky sweet honey garlic chicken to a serving dish. Serve hot, garnished with sesame seeds or green onions if desired, over rice or alongside your favorite vegetables.