Cook pasta according to packaged directions. Save 1 cup (2 deciliters) pasta cooking water once the pasta is cooked.
On a large frying pan over medium-high heat, cook the bacon until crispy. Do not use any oil or butter, since the bacon contains a lot of fat itself. Remove bacon from the frying pan a place on kitchen paper. Do not discard the bacon grease.
Reduce heat and add olive oil, onion, and garlic to the bacon grease. Stir constantly for 2 minutes until the onion and garlic have softened.
Add thyme, oregano, and mushrooms and cook for about 10 minutes.
Add 1 cup of pasta water, heavy cream, and bring to a gentle boil. Let cook for 1-2 minutes and add afterwards the drained pasta. Cook until the sauce thickens and the sauce sticks to the pasta.
Add butter, parmesan cheese, and stir well. Serve with cooked bacon and chopped parsley.