Pat short ribs dry. Season with salt and pepper.
Warm half of your oil in a skillet over medium-high heat and sear the short ribs on all sides.
Add onion, celery, and carrots to the skillet along with the remaining oil.
After cooking for 1 minute, add garlic and red wine to deglaze the pan. Add balsamic vinegar, tomato paste, beef broth, rosemary, and bay leaves.
Add short ribs to the slow cooker and the vegetable mixture. Cook on low for 6-8 hours.
Serve crockpot short ribs over mashed potatoes, rice, or pasta. Enjoy!