• Preheat the oven to 325°F

For the Lamb Shanks:

• Place the lamb shanks on a work space and blot the moisture with paper towels.  
• In a small dish combine the garlic powder, onion powder, cumin, paprika, salt, and pepper.   Sprinkle the lamb shanks generously and rub into the surface.
• Heat the oil in a large Dutch oven, or a brasier pot set over medium-high heat. Add the lamb shanks and sear on all sides, about 2-3 minutes. Transfer to a plate and set aside.
• In the same pot add the onion and cook until soft, about 3 minutes; then add the garlic and cook for 30 seconds.  Add the lemon juice, wine and beef broth. Toss in the bay leaves and the dried oregano.  With kitchen string tie the thyme and rosemary together and add to the pot.
• Return the seared lamb shanks to the pot.  The liquid should cover the shanks about 3/4, add more broth or water if necessary, and bring the pot to a boil. Cover the pot and transfer to the oven and cook 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. 

To make the Sauce:

• Remove and discard the string with remaining herbs, 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 heat set over medium-high.  Bring the braising liquids to a boil and cook until reduced to about 2 cups. About 5-10 minutes.
• In a small dish combine the cornstarch with 1/4 cup of cold water, stirring until smooth.  Whisk the mixture into the braising liquid and cook until 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.