Add the peeled garlic cloves and water to a pan. Bring to a simmer, cover, and cook for 5 minutes. Remove the lid and continue cooking until the water has evaporated, then transfer the garlic to a plate.
In the same pan, heat a bit of oil over medium-high heat. Add the cubed chicken and cook until about 80% cooked through.
Add the dark soy sauce, light soy sauce, oyster sauce, brown sugar, and the cooked garlic cloves. Continue cooking until the sauce reduces into a glossy glaze that coats the chicken and garlic.
Serve over a fresh bowl of rice if desired.
