Add extra virgin olive oil to a large heavy saucepan over medium heat.
First, add the minced pork to the saucepan and cook until all the liquid from the meat has evaporated for around 5 minutes.
Then add the minced beef and cook until brown, stirring frequently for around 5 minutes.
Once cooked, transfer the meat to a bowl and cover and put it to one side.
Add the butter to the saucepan and melt over medium heat.
Then add the onion, carrot and celery and cook for around 5 minutes until the onions are translucent.
Next, add the tomato puree and sauté for 5 minutes more, stirring occasionally.
Return the meat to the saucepan, turn up the heat and pour in the red wine.
Cook over high heat for 2 minutes, then cover the pan and turn the heat down to low.
Leave the Ragù alla Bolognese to simmer very gently for at least 3 hours.
Stir occasionally so the meat does not become dry.
After the 3 hours of cooking, pour in the milk and cook on low heat for a further 40 minutes.
Serve the Ragù alla Bolognese with tagliatelle for the authentic way or spaghetti if you prefer.