How to Make It
Preheat the oven to 250°. In a mini food processor, chop the garlic. Add the rosemary, thyme, 2 teaspoons of kosher salt and a pinch of pepper and process until the herbs are finely chopped. Rub the lamb all over with the herb salt.
In an enameled cast-iron casserole, heat the oil. Add the lamb and cook over high heat until lightly browned all over, about 8 minutes. Add the stock and bring to a boil. Cover and braise in the oven for about 2 1/2 hours, until the lamb is very tender. Transfer the lamb to a bowl and let rest for 5 minutes. Strain the cooking liquid and skim off the fat. Season the jus with the Worcestershire sauce, brown sugar and salt and pepper; keep warm.
Shred the lamb, discarding any large pieces of fat. Spread the rolls with mustard and top with the lamb and blue cheese. Serve the jus alongside.