How to Make It
Preheat the oven to 375°. Open the leg of lamb on a work surface, fat side down. Drizzle olive oil over the lamb, rub in the chopped herbs and season with salt and pepper. Roll up the lamb, fat side out, and tie with kitchen twine at 1-inch intervals. Season with salt and pepper.
In a small roasting pan, line the bottom with the herb sprigs. Add the lamb and roast in the top of the oven for about 1 hour, until an instant-read thermometer inserted in the meat registers 125° for medium-rare. Transfer to a carving board and let rest for 15 minutes. Strain the roasting juices into a cup and skim off the fat. Discard the strings and thinly slice the roast. Drizzle with the juices, sprinkle with fleur de sel and serve.