1. In a large skillet, heat the olive oil over medium-high heat. Add the onion, carrots, and celery, cooking until they are tender, about 5-7 minutes.
2. Add the zucchini and cook for an additional 3-4 minutes until softened.
3. Push the vegetables to one side of the skillet and add the ground beef and ground pork. Cook until browned, breaking up the meat with a spoon.
4. Stir in the garlic and cook for another minute until fragrant.
5. Pour in the red wine and simmer until it is mostly evaporated.
6. Transfer the mixture to your slow cooker and add the crushed tomatoes, beef broth, tomato paste, oregano, basil, thyme, salt, pepper, and bay leaf.
7. Cover and cook on low for 6-8 hours, stirring occasionally.
8. About 30 minutes before serving, stir in the whole milk and continue to cook.
9. Remove the bay leaf and stir in the fresh parsley just before serving
