01 - Generously season beef short ribs with salt and black pepper on all sides.
02 - Heat a large skillet over medium-high. Sear the short ribs for 2 to 3 minutes per side until browned, then transfer to the slow cooker.
03 - In the same skillet, sauté chopped onion, carrots, celery, and minced garlic for 3 to 4 minutes until slightly softened. Add vegetables 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 - Add thyme, rosemary, and bay leaves to the slow cooker.
06 - Cover and cook on LOW for 8 hours, or until the ribs are fork-tender and meat pulls from the bone easily.
07 - Carefully remove herb sprigs and bay leaves from the cooked dish. Skim off rendered fat as needed.
08 - If a thicker sauce is desired, combine cornstarch with cold water and stir into the slow cooker. Cook on HIGH for 10–15 minutes or until sauce reaches desired consistency.
09 - Portion short ribs with sauce and vegetables. Serve immediately while hot.