In a small bowl, mix together brown sugar, salt, black pepper, garlic powder, onion powder, smoked paprika, chili powder, cumin, and celery seed to create a flavorful dry rub.

Pat the pork chops dry with paper towels. Generously rub the spice mixture on both sides of each chop, ensuring they are well-coated.

Place the seasoned pork chops in the slow cooker. Drizzle a small amount of barbecue sauce on each layer, saving ¼ cup for later basting.

Cover and cook on low for 5-6 hours or on high for 3-4 hours. The pork chops should be fork-tender when done.

Once cooked, carefully transfer the chops to a baking sheet. Brush them with the reserved barbecue sauce, then broil on high for about 1 minute until the sauce is glossy and sticky.

Sprinkle chopped parsley over the pork chops before serving for a fresh touch and added color.