Bring a pot of water to boil and cook rice according to instructions.
In small bowl, whisk together light brown sugar, soy sauce, chicken stock, rice wine vinegar, peanut butter, sesame oil, ginger, ¼ cup water and 1 tbsp cornstarch and set aside.
Beat egg in mixing bowl. Add chicken cubes with granulated sugar, salt and pepper. Coat chicken with ⅓ cup cornstarch.
Heat 2 tbsp of the oil in a wok or cast iron skillet over medium-high heat until shimmering. Add half the chicken to skillet and cook for 3-4 minutes per side, until lightly browned. Add 1 tbsp oil and repeat with remaining chicken. Remove and set aside.
Add garlic, green onions and dried chilis and cook for about 1 minute.
Return chicken to skillet and add sauce. Cook for a couple of minutes or until the sauce starts to bubble and thicken.
Sprinkle the chicken with some green onions and sesame seeds and serve over rice.