For the Gremolata:
Combine all ingredients in food processor and pulse until mixture begins to stick together. Set aside.
For the Carrot Purée:
Boil the carrots until tender, about 8 to 10 minutes, then transfer to blender and puree until smooth. Reserve for risotto. You should end up with about 1 cup of puree.
For the Carrot Risotto:
Heat a large skillet over medium heat. Add 2 tablespoons of olive oil and the onions. Cook for 4 to 5 minutes until onions are tender. Add the garlic, carrots, rice and butter and cook for 3 to 5 minutes or until rice begins to lightly color.
Deglaze with white wine and cook until the liquid is reduced to a thick syrup. Stir in the chicken stock very slowly. Cook the risotto until slightly al dente, 6 to 7 minutes. When the rice is cooked, stir in the carrot puree and season to taste. Stir in the cheese and serve immediately.
For the Roast:
Preheat oven to 350 degrees.
Butterfly the leg of lamb and spread gremolata on the meat. Tightly roll the lamb and secure with butcher’s twine.
Place the vegetables in the bottom of a large roasting pan. Season the lamb and place on top of the vegetables. Cover. Cook on center rack in oven until meat reaches an internal temperature of 140 degrees. Allow lamb to rest for 15 minutes before slicing.