The important thing to remember about cooking a leg of lamb is to not over-cook it. Lamb is naturally tender.
You can get a leg of lamb bone-in (“avec os”) or boneless (“sans os” or “désossée”).
Regarding the cooking time question, it is said to cook a leg of lamb 15 minutes / 500 g.
So if you bought a 2 kilos leg, you will cook it for 1 hour.
For one leg of lamb (2,5 kg) you need :
3 cloves garlic cut into 2 pieces,
3 leaves of thyme (fresh or dried)
2 Tbsp olive oil
Salt and pepper
Preheat oven to 210°C.
Place lamb in a roasting pan, with a knife make small holes and insert garlic (we say “piquer avec de l’ail” or “piquer à l’ail”). Generously salt and pepper all sides of the roast, pour olive oil on it.
Roast at 210°C for 20 minutes, then reduce the heat to 180°C and roast an additional hour.
Lamb should never be cooked until well done or it will be too dry.
Slice with a sharp carving knife. Serve with some vegetables or gratin.