01 - Generously season beef short ribs with salt and black pepper on all sides.
02 - In a large skillet set over medium-high heat, sear short ribs on all sides for 2 to 3 minutes per side, then transfer to the slow cooker.
03 - Add chopped onion, carrots, celery, and minced garlic to the skillet. Sauté for 3 to 4 minutes until vegetables are slightly softened, then transfer to the slow cooker.
04 - Pour beef broth and red wine into the slow cooker. Stir in tomato paste and Worcestershire sauce until well combined.
05 - Arrange thyme sprigs, rosemary sprigs, and bay leaves on top of the mixture in the slow cooker.
06 - Cover and cook on LOW for 8 hours, or until the ribs are exceptionally tender and the meat easily separates from the bone.
07 - Remove herb sprigs and bay leaves. Skim excess fat from the surface, if needed.
08 - To thicken the sauce, combine cornstarch with water and stir into the slow cooker. Cook on HIGH for 10 to 15 minutes until the sauce reaches the desired consistency.
09 - Serve the beef short ribs hot, accompanied by the sauce and vegetables.