Place the four breasts in a gallon zip lock bag with two cups of the White Barbecue Sauce and marinate four hours or overnight.
Heat grill to high.
Remove chicken from bag and discard marinade. Rinse the chicken and pat dry with paper towels.
Brush three tablespoons of olive oil over the skin and sprinkle with the salt and pepper.
Place skin down on the hot grill and cook two to three minutes just to give grill marks. Brush the back side with the remaining oil and flip. Cook two minutes.
Move the chicken to an upper rack or a cooler side of the grill, skin up and lower the temperature to medium. The internal grill heat with cover closed should hover around 425 degrees F.
Take the one cup of White Barbecue Sauce and brush a small amount onto the tops of the breasts. Cover grill and wait five minutes. Brush again and again close the lid and time five minutes.
Do this one more time. (Each time you do this, the sauce cooks into the chicken and eventually the tops get crispy and caramelized.)
After the final sauce goes on, cover the grill and cook another 10-20 minutes or until the internal temperature reaches between 160 and 162 degrees F, using a probe thermometer. (The internal temp of the chicken should rise to 165 degrees F as it rests.) Total cooking time should be about 30 minutes but your time may vary based on the size of the breast.
Remove to a platter, brush a little of the remaining sauce on top and let rest five minutes.