Rinse the pork chops and pat dry with paper towels. Sprinkle salt and pepper over chops, then dredge in flour to lightly coat. Reserve the remaining flour.
In large, deep skillet, heat oil over medium heat. Add two of the pork chops and cook, turning once until well browned, about 5 minutes per side. Transfer the chops to a plate. Repeat with remaining chops.
Add onions and garlic to the fat in the pan and cook, stirring, for 1 minute. Reduce the heat to low and add reserved flour. Cook, stirring, until it begins to brown, about 8 minutes.
In a small bowl combine the stock, water, Worcestershire, vinegar, mustard, molasses and allspice. Add to pan and stir until well incorporated. Bring to a boil, then reduce the heat to maintain a simmer. Return the pork chops and their accumulated juices to the pan.
Cover and simmer until the chops are very tender, about 45 minutes, turning the chops halfway through cooking. Serve hot.