Mix together all of the ingredients except the chicken, cornstarch, and garnish. Measure out 1 cup of the marinade, and set it aside.
12 oz pineapple juice, 1/2 cup soy sauce, 1/2 cup brown sugar, 1/4 cup seasoned rice wine vinegar, 1/3 cup ketchup, 1 tsp minced garlic, 1/2 tbsp ginger paste, 1 tbsp Worcestershire sauce
Add the chicken breasts to a large ziplocking bag and pour the rest of the marinade into the bag. Seal and refrigerate for 4 hours, flipping the bag every 30 minutes.
4 lbs boneless, skinless chicken breasts
Pour the reserved cup of marinade into a skillet. Add the cornstarch, whisking until evenly combined. Heat the mixture, whisking often, just until slightly thickened. Set aside, and it will continue to thicken some as it cools.
1 tbsp cornstarch
Using tongs, transfer the marinated chicken breasts to a grill and cook over medium heat. Discard the excess marinade.
Grill the chicken, turning often and brushing thickened sauce on top after each turn, until it has cooked through to a temperature of 160°.
Transfer the grilled chicken to a serving dish, and brush the remaining sauce evenly out over all of the chicken.
Sprinkle green onions and sesame seeds evenly out overtop, then serve warm and enjoy!
thinly sliced green onions, toasted sesame seeds