Heat a large skillet over medium heat. Add butter and oil. Once the butter is melted, add the onion and garlic. Cook until the onion is starting to get soft.
Turn the temp up to medium high and add the pancetta, cook until crispy. Remove the casings from the sausage then add to skillet and brown. Pour in the wine and scrape up those delicious browned bits.
Toss in the mushrooms and stirring occasionally, cook till they are slightly softened.
Add the tomatoes (any extra juices too), basil and oregano, and salt to taste, and stir to combine. Turn heat to low, cover and simmer for one to two hours, stirring occasionally.
While the sauce is simmering, cook the pasta (make sure you have good salty water) until just al-dente. Drain the pasta, reserving 1/2 cup pasta water (DO NOT RINSE).
Back to the skillet -- add the spinach and cook till it begins to wilt. Then toss in the pasta and stir to combine everything -- stir frequently until everything is heated through. (add some reserved pasta water if the sauce seems too thick)
Spoon into bowls and top with fresh Parmesan cheese. Enjoy!