How to Make It
In a medium enameled cast-iron casserole, heat 2 tablespoons of the olive oil until shimmering. Season the lamb with salt and pepper and add half of the meat to the casserole in a single layer. Cook over moderately high heat, turning once or twice, until browned all over, about 7 minutes. Transfer the lamb to a plate and pour off the oil. Add 2 more tablespoons of olive oil to the casserole and repeat with the remaining lamb. Wipe out the casserole.
Add the remaining 1/2 cup of olive oil to the casserole. Add the onion and garlic and cook over moderate heat until the onion is softened.
Return the lamb and any accumulated juices to the casserole. Add the wine and rosemary and bring to a boil, scraping up any browned bits from the bottom. Cover and simmer over moderately low heat until the lamb is tender, about 1 1/4 hours.
Uncover the casserole and simmer the stew until the liquid has nearly evaporated, about 20 minutes. Remove from the heat and discard the rosemary sprig.
Meanwhile, in a medium bowl, whisk the eggs with the cream. Whisk in the Parmesan, parsley and lemon zest.
Using a wooden spoon, stir the egg mixture into the lamb stew. Cook over low heat, stirring gently, until the the eggs just begin to set and the sauce is thick and creamy, about 5 minutes. Transfer the stew to a bowl and serve.