Heat enough olive oil to cover the bottom of a large pot. Add chopped onion and cook for about 5-7 minutes to brown.
Cut the Italian sausage into halves and add to the pot with ground meat and cook until brown. Add parsley and garlic and cook for about 2 minutes. Add tomato paste and stir for about 5 minutes.
Pour stewed tomatoes into a separate bowl and squeeze with your hands to break them up a bit. Add them to the pot along with chopped basil, crushed tomatoes, wine and a pinch of sugar. Sprinkle 1 tsp. of dried oregano on top of the sauce and bring to a high boil. Reduce heat and simmer for about 45 minutes.