Heat 3 tablespoons vegetable oil in a nonstick pan over medium heat. Sear the chicken on both sides, until it begins to brown, around 5 – 10 minutes on each side. You might need to do this in batches.
Make the sauce: Heat the remaining 3 tablespoons oil in a large sauce pan (large enough to hold the chicken pieces as well) over medium heat. Add the minced garlic and allow to fry until fragrant but not burnt. Add the pineapple juice and the cornstarch mixture. Mix well.
Add the rest of the sauce ingredients and stir everything together over medium heat until the sauce thickens. Adjust the seasoning to your preference.
Lower the heat and add in the chicken and cook, covered, for 30 – 45 minutes or until chicken is cooked tender.
In the last 5 minutes of cooking, increase the heat to high and cook until the sauce has reduced, thickened and is slightly sticky. Frequently stir everything together to stop it from burning. When done remove from heat and serve warm. Enjoy!