Instant Pot Lamb Shanks

Sear the Lamb Shanks: Set the Instant Pot to sauté mode. Add olive oil and sear lamb shanks for 7-10 minutes, until browned on all sides. Set them aside.
Cook Vegetables: Add the chopped onion and sauté for 5-7 minutes until softened. Then add carrots, celery, and garlic, cooking for 2-3 more minutes.
Add Tomato Paste: Stir in tomato paste, cooking for 2 minutes.
Add Broth & Seasonings: Add beef broth, Worcestershire sauce, thyme, oregano, bay leaves, and salt. Stir well.
Pressure Cook: Return lamb shanks to the pot, tucking them into the liquid. Close the lid and cook on high pressure for 50 minutes. Let pressure release naturally for 10 minutes, then manually release the remaining pressure.
Thicken the Sauce: Remove the lamb shanks. Mix cornstarch with 1/4 cup water, add to the sauce, and let simmer until thickened.
Serve: Plate the lamb with mashed potatoes or vegetables, topped with the sauce.