Place the carrots, celery, onion, and garlic in a food processor and pulse until minced.
Heat the olive oil in a French Oven over medium heat.
When it starts to shimmer, add the minced vegetables and cook for 10 minutes until soft and translucent.
Increase the heat to high, and add the beef, pork, pancetta and butter. Cook for 10 minutes until browned, regularly stirring to prevent anything from sticking to the bottom of the pan.
Add the red wine and cook for 5 minutes.
Add the milk and cook for an additional 2 1/2 minutes.
Add the Passata, Thyme, salt and mix.
Cover and cook for 4 hours on medium low heat to allow the flavours to blend.