Heat olive oil in a large skillet over medium heat. Add the lamb shanks and cook until browned on all sides, about 10 minutes. Transfer to a slow cooker.
Add the onion, garlic, thyme, oregano, beef broth, carrots, celery, and bay leaf to the slow cooker. Season with salt and pepper.
Cover and cook on low for 8-10 hours, or on high for 4-6 hours, until the lamb is tender.
Serve the lamb shanks over cooked vegetables and herbs, if desired.
Interesting Facts
Lamb shanks are a great source of protein, iron, and B vitamins.
Braised dishes are cooked slowly in a liquid, usually with a lid on, and are often served with a sauce.
Herbs such as thyme, oregano, and bay leaf add flavor and aroma to dishes.