Sprinkle boiler with salt and pepper. In a large ovenproof skillet, melt butter over medium-high heat. Brown pork chops, turning once, for about 1 minute per side; transfer to a plate. Add garlic and onion to pan and sauté for about 2 minutes or until starting to brown. Add BBQ sauce and water and bring to a boil, scraping up bits stuck to pan.
Return pork chops to pan and turn to coat in sauce; reduce heat and simmer for 3-5 minutes or until just a hint of pink remains in pork. Place cheese slices evenly on top of each pork chop. Broil for about 2 minutes or until cheese is bubbling.