1. Heat a large nonstick skillet over medium-high heat. Add onion, celery, carrot, and garlic to pan; sauté 4 minutes. Add beef, pork, and veal to vegetable mixture. Cook 5 minutes or until browned; stir to crumble. Drain meat mixture; place in a 6-quart electric slow cooker. Stir in tomatoes and remaining ingredients. Cover and cook on LOW for 8 hours. Remove and discard bay leaf.
Freezer Tip: The beauty of bolognese? It freezes well. Make it ahead to have on hand for busy weeknights.