To make the marinade, place the soy sauce, honey, vinegar, oyster sauce, mustard and five spice in a bowl, and stir to combine. Add the chicken and toss to coat, then set aside for at least 30 minutes to marinate.
Preheat the oven to 200°C. Transfer chicken to a small roasting pan and roast, turning every 15 minutes, for 45 minutes or until cooked through. Remove chicken from the pan and transfer the sauce to a small saucepan over medium heat. Bring to the boil and simmer for 4 minutes or until reduced and thickened. Pour the sauce over the chicken then sprinkle with the sesame seeds. Keep warm.