01 - Heat olive oil in a large skillet over medium heat. Add pancetta, onion, carrots, and celery; sauté for 5 to 7 minutes until softened.
02 - Stir in minced garlic and cook for 1 minute until fragrant.
03 - Add ground beef (and pork if used), break apart with a spoon, and cook until no longer pink, about 5 minutes.
04 - Transfer meat mixture to slow cooker. Add crushed tomatoes, tomato paste, red wine, broth, oregano, basil, bay leaf, red pepper flakes, salt, and pepper; stir to combine.
05 - Cover and cook on LOW for 6 to 8 hours or on HIGH for 3 to 4 hours until thick and flavorful.
06 - Remove bay leaf. Adjust salt and pepper to taste.
07 - Serve sauce hot over pasta and garnish with fresh parsley or basil.