Chop the vegetables very finely. If you want to speed up this step, you can use a food processor.
Heat extra virgin olive in a large saucepan. Add the onions, carrot and celery. Cook for around 10 minutes on medium-low heat until vegetables are softened.
Add beef and pork mince. Break it apart with a wooden spoon and stir constantly until the meat is browned.
Deglaze with red wine.
Transfer your meat and vegetable mixture in the slow cooker. Add tomato puree, salt, pepper and cover with broth.
Cook on low for 6 hours.
Finally, when the sauce ready, add the milk to round up the flavor.
Cook pasta according to directions and top with bolognese.