- 1 (7 pound) leg of lamb, fat trimmed to 1/4-inch
- 12 anchovy fillets, packed in oil
- 12 cloves garlic, peeled and halved lengthwise
- 1/4 cup duck fat
- 3 tablespoons chopped fresh rosemary
- 1 tablespoon Essence 
- 1 teaspoon salt
- 1 teaspoon freshly ground black pepper
- 1 large yellow onion, peeled and quartered
- 1 large carrot, cut into 2-inch pieces
- 1 large turnip, trimmed and quartered
- 2 stalks celery, trimmed and cut into 2-inch pieces
- 1/2 cup dry red wine
- 1 cup rich chicken or beef stock
- 2 tablespoons cold unsalted butter, cut into 4 pieces
- Preheat the oven to 350 degrees F.
- With a small, sharp knife, make 12 (1 1/2-inch deep) slits about every 2 inches of the lamb. Wrap the anchovies around the garlic cloves and stuff into the slits.
- In a large roasting pan set over 2 burners, heat the duck fat over medium-high heat. Add the lamb and sear, turning, on all sides, about 5 minutes. Remove from the heat and, in a small bowl, combine the rosemary, Essence, salt, and pepper, and rub evenly over the meat. Add the vegetables, and stir to coat with the fat. Roast until an instant-read meat thermometer inserted into the thickest part of the leg reads 130 degrees F for medium-rare, about 1 hour and 15 minutes, stirring the vegetables every 30 minutes.
- Remove from the oven, transfer to a large platter, and cover loosely to rest for 15 minutes. Place the pan over 2 burners over medium-high heat. Add the wine and cook, stirring, to deglaze the pan and reduce by half. Add the stock and stirring, reduce again by half. Strain into a small saucepan through a fine mesh strainer, pushing down on the vegetables to extract as much liquid as possible. Return to medium heat, and stirring constantly, add the butter a piece at a time. Remove from the heat and cover to keep warm.
- Carve the lamb, and if desired, serve with the roasted vegetables on the side. Serve with the gravy.