Heat large stock pot over medium heat. Add olive oil, celery, carrot and onion. Cook for 10 minutes. Do not brown onions.
Add garlic and bacon to pot. Stir to combine with vegetables. Saute for 5-8 minutes.
Add ground pork and ground beef to pot. Breaking up meat into small pieces. Cook for 5-10 minutes until meat is no longer pink.
Add chicken stock, wine, tomato paste and sage leaves to pot. Stir until well combined.
Bring mixture to boil. Reduce heat to a low simmer. Place lid on pot to only partially cover. Simmer sauce for at least 2 hours. Stir occasionally. Do not let dry out...add a bit more chicken stock if needed or make sure to reduce heat to lowest setting.
After 2 hours of simmering, some of the liquid should have evaporated. Now add butter, heavy cream and Parmesan cheese. Stir and let simmer for a few minutes.
Taste. Now add salt and pepper to your taste. Stir well. Let simmer a couple more minutes. Continue to taste for seasoning until satisfied.
Serve by tossing with pasta or zucchini noodles. Top with additional parmigiano reggiano cheese and chopped fresh parsley.