1. Stir together the ketchup, broth, vinegar, brown sugar, lemon juice, Worcestershire sauce, onion powder, dry mustard, salt and pepper in a large saucepan over medium-high. Bring to a boil, stirring occasionally. Reduce heat to low and simmer, stirring occasionally, 1 hour.
2. Heat the oil in a medium skillet over medium-high. Add the bell pepper, onion and garlic, saute 5 minutes. Stir the vegetable mixture and the pulled pork into the sauce, and simmer, about 40 minutes.
3. Divide the cooked spaghetti evenly among 6 bowls. Spoon the pulled pork sauce over the spaghetti, and sprinkle with the cheese and the parsley.