Season the lamb shanks generously on all sides. Pour oil into preheated oven-proof pot with a wide base. Patiently sear lamb shanks on all sides on medium-high heat. Avoid overcrowding pan and do them in batches if necessary. Place seared shanks onto plate and set aside.

Add to the same pot the onions, celery and carrots. Scrape the browned bits at the bottom of the pot with a wooden spoon while mixing the vegetables to caramelize and sweat (approximately five minutes). Add tomato paste and stir well with vegetables until evenly distributed.

Add the red wine, thyme, and bay leaves. Bring to a vigorous boil and allow to reduce by half (15 minutes). Add the beef stock, pre-seared lamb shanks, and potatoes to the pot and allow liquid to return to a boil.

Cover well with fitted lid or foil and place into a preheated oven at 350 degrees Fahrenheit for two hours.

Remove the pot from the oven and stir in the peas right before serving. Carefully arrange lamb, potatoes and vegetables onto platter. Allow remaining liquid to boil over high heat and reduce by more than half. You should have a syrupy texture to your sauce. Strain and pour over arranged platter and serve.

Make the Gremolata: Mix the ingredients and let stand for 10 minutes to infuse the oil.

Garnish lamb shanks with some more fresh peas and serve with the Italian Gremolata.