In an ovenproof 10-inch saucepan or Dutch oven over high heat, heat the oil. Before it begins to smoke, add the diced onions and cook until they begin to brown, about y minutes, stirring occasionally. Add the pork and the garlic to the pan. Sprinkle the flour over the top, and then stir to evenly coat the pork. Cook for 1 to 2 minutes. Add the wine and cook until it has evaporated, scraping any brown bits off the bottom of the pan. Add 2 cups of the beef stock and the tomatoes, crushing the tomatoes with a fork. Bring to a simmer, and then set the pan over Indirect Medium heat. Cover the pan and cook for 1 hour, occasionally stirring all the way to the bottom [the liquid should simmer slowly]. Uncover the pan and cook for another hour, stirring occasionally. Add the potatoes and continue to cook, uncovered, until the pork and potatoes are fork tender, 45 to 60 minutes longer. If the sauce is getting too thick, add a little more beef stock. Add the parsley. Mix well. Season with more salt and pepper to taste. Serve warm.