Cook the chicken in batches, about 8 minutes per side, until crispy. Transfer the pieces to a plate.
Add the garlic to the Chef Supreme Casserole and cook, stirring constantly, for about 2 minutes. Transfer the garlic to the plate with the chicken.
Turn off the heat, and pour off the fat from the casserole.
Return the Chef Supreme Casserole to the stove and turn the heat up to medium high. Add the water, and scrap up all of the brown bits. Add the brown sugar, and cook for about 5 minutes, until thickened.
Add the vinegar, and stir until the crystalized sugar dissolves
Add the ginger, chicken stock and soy sauce. Add the chicken, skin side up, along with the garlic. Bring the mixture to a boil. Reduce the heatand simmer for about 25 minutes, until the chicken is fully cooked. Transfer the chicken to a plate.
Bring the sauce to a boil and cook until thick, about 8 to 10 minutes. Add the chicken back into the Chef Supreme Casserole and coat with the sauce. Sprinkle with the spring onions.