Directions

1. Place beef and pork on parchment lined baking sheet and freeze 20 minutes. Attach KitchenAid® Metal Food Grinder Attachment with coarse grinding plate to KitchenAid®Stand Mixer. Position mixer bowl under attachment. Turn mixer to speed 4 and grind beef and pork.
2. Heat olive oil and butter in large pot over medium heat. Add onions, carrots and celery. Cook, stirring frequently until soft and beginning to brown. Season with salt and pepper and continue cooking on low for 10 to 15 minutes longer.
3. Increase heat to medium and add beef, pork and pancetta to pot and cook until browned, about 10 to 15 minutes. Add tomatoes and wine and bring to a simmer, scraping up browned bits from bottom of pan. Stir in tomato paste. Reduce heat to low and simmer 1 hour.
4. Warm milk in small saucepan over medium heat and slowly add to sauce. Continue simmering 5 to 10 minutes, adding stock 2 tablespoons at a time if needed, until sauce reaches desired consistency. Can be made up to 2 days ahead.
5. Serve warm sauce immediately with freshly cooked pasta and grated Parmesan cheese.