In a large casserole dish, heat the oil and 50g butter. Brown the pancetta lightly for about 5 minutes.
Add carrots, celery, onions and garlic and cook over a low heat for approximately 10 minutes until softened, adding the remainder of the butter if necessary. Add minced beef and minced pork and season. Skin sausages and add the meat to the pan. Fry while breaking up the meat with a wooden spoon. Cook for 10 minutes stirring occasionally.
Add wine, increase heat to medium and cook for 10 minutes. Add tomato purée and 200ml stock. Bring to the boil, partially cover and simmer over a low heat for 2 hours, stirring from time to time.
After 1 to 1 1/2 hours add more stock, if sauce is getting dry.
This ragù is great when served with tagliatelle and grated Parmesan cheese.