Preheat oven to 175°C and wash and pat dry lamb shanks with paper towel and h
Heat 1 tablespoon of oil in a heavy based pot over medium-high heat. Sear two shanks in the hot oil until browned on all sides. Repeat with remaining shanks and oil.
Transfer to a plate, tent with foil to keep warm, set aside.
To the pan juices, sauté the carrots and diced onions until softened, (about 3 minutes), then add garlic and cook for 1 minute.
Return the shanks back into the pot; season with 1 teaspoon coarse salt and 1/2 teaspoon ground pepper. Sprinkle with flour, toss well and cook for 4-5 minutes to brown the flour.
Add stock, wine, puree, tomato paste, beef cubes and herbs. Bring to a simmer on the stove.
Cover, transfer to lower part of the oven and cook for 2 1/2 hours, or until the meat is fall apart tender.
Gently transfer the shanks onto a plate; tent to keep warm.
Discard the bay leaves from the sauce and place pot onto stove. Simmer sauce over medium heat until thickened to your desired consistency. You should be left with about 3 cups of sauce thick enough to lightly coat the back of a spoon.
Taste for seasoning and adjust salt and pepper, if desired. Add the shanks back into the pot of sauce.
Garnish with parsley and serve with mashed potato.