1/2 (1.1 ounce) package mesquite marinade mix for the grill
2/3 cup water
1 tablespoon vegetable oil
4 (6 ounce) bone-in or boneless pork chops, trimmed of all fat
1 large sweet onion (Walla Walla or Vidalia), cut into 1/4-inch-thick slices
Vegetable oil cooking spray
In a shallow glass or ceramic dish, combine marinade mix, water, and oil, and mix well with a fork. Add pork chops and onion rings. Turn to coat, cover and refrigerate for 30 minutes.
When you are ready to cook, spray a grill rack with cooking spray. Preheat a gas grill to medium or prepare a medium-hot fire in a charcoal grill, with the rack placed 4 to 6 inches above the heat.
Remove pork chops and onion rings from marinade, reserving the marinade. Pour marinade into a small saucepan and bring to a boil.
Place pork chops and onion rings on the grill rack and grill for 10 to 15 minutes or until pork is no longer pink in the center, turning once and brushing frequently with marinade. Discard any remaining marinade.