For the Pork:
Kosher salt, to taste
1/4 C. coarsely ground black pepper
2 T. packed dark brown sugar
2 t. smoked paprika
4 double-cut bone-in pork loin chops (about 1-lb each)
vegetable oil, for the grill
For the Sauce:
4 T. unsalted butter
2 C. diced onions
1 C. apple cider vinegar
3/4 C. packed dark brown sugar
1-1/2 C. ketchup
1-1/4 C. apple juice
1 C. maple syrup
1/2 C. bourbon
1/2 C. prunes
1/4 C. Worcestershire sauce
1/4 t. cayenne pepper
kosher salt and black pepper, to taste
1. Prepare the pork: Mix 2 T. salt (or to taste), black pepper, brown sugar and paprika in a bowl, then rub all over the chops. Wrap in plastic wrap and refrigerate 2-4 hours.
2. Meanwhile, make the sauce: Melt the butter in a saucepan over med heat, then add the onions and cook until translucent, about 4 minutes. Stir in the vinegar and brown sugar until dissolved. Add the ketchup, apple juice, syrup, bourbon, prunes, Worcestershire sauce, cayenne, 1 T. salt and 1-1/2t. black pepper (or to taste) and bring to a boil. Reduce to a simmer and cook until thickened, about 30 minutes. Puree with an immersion blender.
3. Preheat a grill to medium. Brush the grates with vegetable oil, then place the chops directly over the flame and grill until marked and cooked halfway through, about 15 minutes. Turn the chops and place on a cooler area of the grill; cover and cook until a thermometer inserted into the thickest part registers 140 to 145, 15-20 minutes. Uncover and brush the chops on all sides with the prepared sauce, then cover and cook until glazed about 5 minutes more. Transfer to a cutting board and brush with more sauce. Tent with foil and let rest 10 minutes. Serve with more sauce.