• Preheat the oven to 325°F
• Season the lamb shanks generously with salt and pepper. Heat the oil in a large Dutch oven, or a brasier pot over medium-high heat. Add 2 of the lamb shanks and brown well on all sides, about 2-3 minutes. Transfer to a plate and set aside and repeat with the remaining 2 lamb shanks.
• In the same pot add the onion, celery, carrot, fennel, garlic, thyme, rosemary and the bay leaves and cook just until the onions are soft. Return the browned lamb shanks to the pot and add the beef broth and 2 cups of wine. The liquid should nearly cover the shanks, add more broth or water if necessary, and bring the pot to a boil.
• Reduce the heat to low, cover the pot and and transfer to the oven until the meat is very tender, 2 1/2 to 3 hours.
• When the lamb shanks have become tender, carefully transfer them to a platter and cover with foil to keep warm. Strain the cooking liquids through a fine mesh strainer into a saucepan, pressing down on the vegetables with the back of a spoon. Discard the solids left in the strainer, spoon off and discard as much of the fat as possible from the surface of the strained cooking liquids. Return the strained braising liquids to the cook-top set over medium-high and add the remaining 1 cup of wine and the Worcestershire sauce. Bring the braising liquids to a boil and cook until reduced to about 2 cups. About 5-10 minutes.

For the Sauce:

• Meanwhile, in a small dish combine the soft butter and the flour together mashing with a fork or back of a tablespoon to make a paste. When the braising liquids have reduced to 2 cups, remove the saucepan from the heat and whisk the butter/flour paste into the liquid. Return the pot to the heat and cook for another 2-3 minutes until the flour is fully cooked and the sauce has slightly thickened.
• Serve the lamb shanks in individual shallow bowls on top of mounds of mashed potatoes and garnished with chopped parsley.
• Transfer the sauce to a serving pitcher or dish to be served over the lamb shanks.