01 - Generously season the beef short ribs on all sides with salt and black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Sear short ribs for 2 to 3 minutes per side until well browned, then transfer to the slow cooker.
03 - In the same skillet, sauté onion, carrots, and celery for 3 to 4 minutes until softened. Add garlic and cook for an additional minute.
04 - Stir in tomato paste and cook for 1 minute. Deglaze the skillet with red wine or beef broth, scraping browned bits from the bottom of the pan.
05 - Pour the vegetable mixture over the seared short ribs in the slow cooker. Add beef broth, Worcestershire sauce, thyme, rosemary, and bay leaves.
06 - Cover and cook on low setting for 7 hours or on high for 4 to 5 hours, until the ribs are extremely tender and nearly falling off the bone.
07 - Remove bay leaves and herb stems. Skim excess fat from the sauce if desired. Serve the short ribs hot with vegetables and sauce over mashed potatoes, polenta, or noodles.