Cook the pasta al dente. Drain well and set aside. Heat oil in a non-stick skillet over medium heat until hot. Add pancetta or bacon, saute three minutes. Add onions, 1/4 tsp salt and 1/8 tsp pepper. Cover and cook for 15 minutes, stirring frequently. Uncover and cook an additional 10 minutes, stirring often. Remove onion mixture from skillet and set aside. Add mushrooms, 1/4 tsp salt and 1/8 tsp pepper. Cook over medium high heat for 4 minutes. Add oregano and 2 tbl. Parsley. Cook 1 minute. Add garlic and saute one minute. Add onion mixture and broth. Cook until thoroughly heated. Add entire mixture to pasta and toss to coat thoroughly. Divide among 4 dishes or bowls and sprinkle with a little parsley. We also eat this with a little grated parmesan or romano.