01 - Generously season beef short ribs on all sides with salt and black pepper.
02 - In a large skillet over medium-high heat, brown the seasoned short ribs on all sides for 2 to 3 minutes per side, then transfer to the slow cooker.
03 - In the same skillet, sauté onion, carrots, celery, and garlic for 3 to 4 minutes until they begin to soften, 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 - Place thyme, rosemary, and bay leaves on top of the mixture in the slow cooker.
06 - Cover and cook on LOW for 8 hours, until the meat is very tender and pulls easily from the bones.
07 - Remove herb sprigs and bay leaves. Skim excess fat from the surface if necessary.
08 - To thicken, stir the cornstarch and water mixture into the slow cooker and cook on HIGH for 10 to 15 minutes until the sauce reaches desired consistency.
09 - Serve short ribs hot with sauce and cooked vegetables.