1. In a heated sauce pan, sauté chopped onion on low for about 20 minutes.
2. While this is going, boil a pot of water for your pasta. Add salt.
3. Separately, cook four slices of bacon and roughly chop.
4. Once water is boiled, cook pasta for 8 minutes until al dente. Set aside and reserve 1/2 cup pasta water.
5. Add chopped bacon, butter, heavy cream, tomato sauce and Parmesan cheese to sautéd onions. Add in some reserve pasta water depending on desired sauce consistency.
6. Once a sauce is formed, combine cooked pasta.
7. Plate and garnish with grated Parmesan and fresh parsley. Enjoy!