Pat Chicken dry with paper towels

Place Chicken breast side down on a cutting board

Using a good sharp kitchen sears, carefully cut down each side of the backbone and remove (see photos for the step by step process)

You can freeze the backbone and use it later to make chicken stock 

Flip Chicken over and press down on the breasts with both hands to flatten it

Mix together ingredients for the marinade

Place Chicken in a casserole dish and pour marinade over it

Refrigerate and let it marinate at least 4 hours, or overnight for more flavor

Lightly grease the grill grates to prevent sticking

Prepare the grill for medium indirect heat at about 350F. For gas grills (with 3 or more burners), turn all the burners to medium-high heat; after about 10 minutes turn off one of the middle burners and turn the remaining burners down to medium. For charcoal grills, bank one chimney starter-full of lit and ashed-over charcoal briquettes to one side of the grill. 

Place the Chicken breast side up on the indirect side of the grill (discard marinade)

Cover and cook until an instant-read thermometer inserted in the thickest part of the breast (avoiding the bone) reads 160F

Remove with a spatula and place on a platter

Tent with foil and let rest for 15 minutes before cutting into. This will bring the temperature up to 165F and keep the Chicken nice and juicy