Leg of lamb is a traditional and impressive French Easter dish. Though, it can definitely be enjoyed at any other occasions. Make all the prep a day ahead. For a more tender and moister piece of meat, it needs to be taken out of the refrigerator before cooking. If a 10 ounces/300g steak needs 30 min to warm up, a 3kg/6 lb. roast would have to be left out for 3 hours.
Duck fat can be subbed for oil. Mix duck fat with thinly chopped rosemary, thyme and crushed garlic – set aside.
Pat dry the leg with paper towels. To french it, using a sharp boning knife, cut straight into the bone about 1.5-inch/3.5cm from the end, moving the knife all around the bone. Scrap out meat pulling it away using your knife and paper towel. Prior to tie up meat with butcher twine, season the open parts of the meat with the herbed seasoning, salt and pepper.
Depending on what the leg of lamb looks like, you may need to truss it. It helps retain its shape while it cooks in the oven and stops the meat from spreading. Just tie a series of interlinked knots to secure the meat in place; it doesn't have to be perfect. Rub the whole leg with remaining rosemary-garlic seasoning. Some of the garlic cloves may also be inserted into the roast if desired using the tip of your paring knife. Cover roast with foil and refrigerate overnight.
Quarter onions and peel. Wash and peel carrots and cut into chunks. Split garlic head in half – refrigerate until ready to use.
Wash and scrub potatoes. Cook potatoes in salted water for about 25 minutes until just cooked through – do not overcook!. Drain and spread potatoes onto a tray lined with paper towels to cool off. Trimming haricots verts is quick. Just gather small bundles with all of the tough stem ends facing in one direction, and cut just below the stem. Cook beans for about 7 min in a heavily salted water – chill immediately in cold water and drain. Refrigerate cooked green beans in a large container lined with paper towels for up to 5 days.
In order to get a more tender and moist meat, remove roast from refrigerator about 3 hours to allow it to come closer to room temperature before cooking. Uncover and transfer the leg of lamb to a greased wire rack. Use a clean and greased baking tray for the onions, carrots and garlic and add white wine. Season lamb with salt and pepper on all sides. Turn oven on to 390ºF/200ºC. Lower temp to 350ºF/180ºC if using a convection oven. Place the veggies tray on the bottom rack of the oven and leg of lamb above it. Cook lamb for 90 minutes or until internal temperature reads 135ºF/57ºC for medium rare. Keep in mind that temperature continues to rise 5ºC at least once meat is removed from the oven. Always stick the thermometer into the thickest part of the meat without touching the bone. Cook 30 minutes more for medium well. Rotate roast and veggie tray half way through. Remove roast and place rack onto another tray for the juice to drain. Let rest for 30 min or more before carving. This allows the juice to redistribute. Once the meat has rested, remove the string from the exterior of the roast. Save the rendered juice for the gravy.
Save the nicest carrots, onions and roasted garlic for garnishing but leave some for the gravy. Add stock, scrap out bits and transfer everything to the saucepan. Add rendered lamb roast juice and bring to a boil and sieve. Reduce sauce if needed. Readjust seasoning to taste. The sauce can be finished and lustered with butter. Right before serving, throw a couple of chunks of butter and rotate the pan steadily, allowing the butter to emulsify slowly. Keep warm; avoid boiling.
Halve potatoes if desired. In a large frying pan, sauté potatoes with fat, herbs, salt and pepper. Or quickly roast in a 450ºF/230ºC oven until golden brown.
By the time potatoes are roasting, sauté green beans in a hot frying pan with the fat. Season with salt and pepper and sauté for 3 min on high heat. Add garlic and continue to cook until fragrant. Add parsley and remove from the heat.
In a warm and large plater, arrange potatoes, green beans and roasted veggies and top with the roast. Season carved lamb with salt and pepper if desired. Serve it with the hot gravy. Enjoy!
Save leg bone for you next soup, bean stew or lamb stock.