Combine Chicken and Marinade ingredients in a bowl. Marinate for at least 20 minutes, or up to overnight.(if using chicken thighs omit the oil, chicken breast needs the fat content added)
Heat a saute pan over medium high heat. Once hot, add half the oil. Remove the chicken from marinade (reserve marinade) and place in the pan. Sear both sides until nicely browned, then remove from the pan and set aside.
Heat the remaining oil in the pan over medium heat. Saute the garlic and onion until softened. Add the reserved marinade, water, sugar and season with black pepper. Bring it to a simmer.
Add chicken the chicken to the pan and cook to an internal temperature of 160 degrees using a thermometer. Remove the chicken and set aside, continue to simmer the sauce until it reduces down to a thick jam-like syrup. Then remove the pan from the heat.
Spoon the sauce over the chicken. Garnish with scallions. Serve with bread.