Cut the carrot, celery and onion very fine (but not too much that it becomes pulpy when cooked).
In a medium to large heavy pot add the olive oil and chopped vegetables, cook covered on low heat (stirring occasionally) until onion is transparent.
Increase the heat to medium and add the ground beef and pork. Stirring as the meat is cooking to break up the pieces. Once the meat has browned turned the heat up to high and add the wine.
Cook until the alcohol has evaporated (about 20-30 seconds) and the liquid has evaporated. Decrease the heat to medium/low and add the tomato paste, puree, salt, pepper and bay leaf. Gradually decrease the heat to the lowest setting cover and let simmer for three hours (the mixture should not boil). Stir occasionally.
After the time has passed remove the bay leaf and add the milk, heat thoroughly for a couple of minutes. Serve over cooked pasta. Enjoy!
Notes
Why Add Milk To The Bolognese Sauce?
The milk (sometimes heavy cream is used in the Bolognese sauce) is generally added if the pasta you are serving it with is a dry pasta, it is added at the end of the cooking time. But if you are using a fresh egg pasta, such as tagliatelle, adding it is optional. I always add it because I like the taste and flavor it gives the sauce.
What Is The Best Red Wine To Use?
A medium-bodied red wine with a moderate tannins, like a Cabernet Sauvignon, Merlot or Pinot Noir is the best to use. A wine you would drink is always the best choice.
Can You Use White Wine?
Red wine is always considered better to use with meat dishes and white with fish dishes, but if you are out of red and only have white you could definitely use it.
How to store it
Any leftover sauce should be stored in an airtight container and refrigerated it will keep for up to 5 days in the fridge. The completely cooled sauce can also be frozen. Place in a freezer safe container, it will keep for up to 3 months. Thaw the sauce overnight in the fridge.