01 - Generously season beef short ribs with salt and black pepper on all sides. In a large skillet over medium-high heat, sear the ribs for 2 to 3 minutes per side until well-browned. Transfer browned short ribs to the slow cooker.
02 - In the same skillet, add onion, carrots, celery, and garlic. Sauté for 3 to 4 minutes until vegetables are just softened, then transfer to the slow cooker.
03 - Pour beef broth and dry red wine into the slow cooker. Stir in tomato paste and Worcestershire sauce until evenly combined.
04 - Nestle thyme, rosemary sprigs, and bay leaves among the short ribs in the cooker. Cover and cook on LOW setting for 8 hours, until meat is exceptionally tender and easily separates from the bone.
05 - Discard herb sprigs and bay leaves. Skim and remove excess fat if necessary. For a thicker sauce, stir cornstarch mixture into the slow cooker and cook on HIGH for 10 to 15 minutes until sauce reaches desired consistency.
06 - Serve short ribs hot, accompanied by the vegetables and sauce.