Either very finely chop or process the onion, carrot, celery stalk and garlic in a food processor.
Warm up the olive oil in a big heavy pot, add the chopped vegetables and fry on medium heat, often stirring for 3-5 minutes.
Increase the heat to high and add the two types of minced meat; fry constantly stirring till the meat is no longer pink.
Add all of the tomatoes, bay leaves, sugar, some salt and pepper (you will adjust the taste at the end, so don’t add too much at this stage), and half a cup of wine; once everything starts to boil, decrease the temperature to low and cook for 3 hours.
During the cooking time, stir the sauce at least every half an hour to break any bigger pieces of meat or tomatoes and to prevent everything from sticking to the bottom of the pot. Each time you stir, add half a cup of the red wine till you have used all of it.
After the 3 hours of cooking, check the seasoning. The sauce should be thick and without lumps of meat. If there are any, you can break them with a potato masher.
Serve the sauce with your choice of pasta cooked al dente (the best is not spaghetti but wider type like tagliatelle or pappardelle) and grated Parmesan cheese.