01 - Pat the beef short ribs dry and season evenly with salt and black pepper on all sides.
02 - Heat a large skillet over medium-high heat. Sear the short ribs for 2 to 3 minutes per side until well browned. Transfer browned ribs to the slow cooker.
03 - In the same skillet, add chopped onion, sliced carrots, celery, and minced garlic. Sauté for 3 to 4 minutes until aromatic and slightly softened, then add the mixture to the slow cooker.
04 - Pour beef broth and red wine into the slow cooker. Stir in tomato paste and Worcestershire sauce until thoroughly combined.
05 - Nestle thyme sprigs, rosemary sprigs, and bay leaves among the ribs and vegetables in the slow cooker.
06 - Cover and cook on low for 8 hours, or until the beef is exceptionally tender and easily separates from the bone.
07 - Remove herb sprigs and bay leaves. Skim any excess surface fat if necessary.
08 - For a thicker sauce, stir in the cornstarch and water slurry. Set slow cooker to high and cook for 10 to 15 minutes until the sauce is thickened.
09 - Serve short ribs hot, pouring sauce and vegetables over the top.