Pat the lamb shanks dry and sprinkle with salt and pepper all over the lamb shank.

Heat 2 tbsp of olive oil in a Dutch oven over high heat. When the pot is hot, sear the lamb shanks in 2 batches. About 2 minutes on each side, until brown all over. Remove lamb onto a plate and drain excess fat from the pot.

Over medium-low heat, heat remaining 1 tbsp of olive oil in the same pot. Add the onion and garlic, saute for 3-4 minutes. Add carrot and celery. Cook for 5 minutes until onion is translucent and sweet.

Add the red wine, chicken stock, crushed tomato, tomato paste, thyme and bay leaves. Stir to combine.

Place the lamb shanks into the pot until the meat is mostly submerged.

Turn to medium-high heat and bring to an energetic simmer. Cover, then transfer to the oven for 2 hours.

After 2 hours, remove lid and cook for another 30 minutes.

After 2.5 hours, check to ensure lamb meat is tender by using two forks to pull the meat apart. If not, cover and keep cooking.

Remove lamb onto plate and keep warm. Pick out and discard bay leaves and thyme.

Strain the sauce into a bowl, pressing to extract all sauce out of the vegetables. Alternatively, you can use a hand blender and blitz the sauce into a thick puree. Bring to simmer over medium heat. Add salt and pepper to taste.

Serve the lamb shanks on mashed potato. Garnish with thyme leaves if desired.