BUTTERFLY THE CHICKEN:
Remove neck, giblets and cut away excess fat from 1 whole roasting chicken.
Take a pair of kitchen sheers and cut along both sides of backbone to remove it (inbetween wings). Open up, flatted, turn over skin up.
Turn chicken skin-side up and press down between the breasts to break the keel bone. This will allow the chicken to lay very flat on grill and cook quickly.
In a small bowl, combine the Chinese five-spice and ground ginger. Sprinkle liberally over all sides of chicken. Set aside.
In a small pot over medium-high heat, combine the hoisin sauce, rice vinegar, pre-minced ginger (from a jar) and the brown sugar. Bring to a boil for 3 minutes before using.
Set up outdoor or indoor grill on medium heat. Oil grate when ready to start cooking.
Place chicken on preheated grill. Flip after 15 minutes and glaze top. Turn and brush every 15 minutes until internal temperature of the thigh is 180 degrees F, about 45 minutes total. Transfer to cutting board and let it rest 5 minutes before cutting.
Sprinkle the chicken with sesame seeds and serve.