Once or twice a year we do a roast leg-o-lamb. I say we because I go to my folks place, Redquarters, because their oven is more trustworthy.
What you need: 1 3-4 pound leg of lamb (I get boneless. It costs a little more but there’s less wastage and I don’t make broth from the bone anyway.)
several tablespoons olive oil
several tablespoons (3-4 cloves) minced garlic
1-2 T dried thyme (or oregano)
Preheat oven to 450 F. Drain excess blood or other moisture from lamb. Spray roaster pan with non-stick spray (optional but I’m doing the dishes and I don’t like scraping).
Now the next bit gets a little messy, so you’d better roll up your sleeves and shoo the cat, dogs, and small children out of the way. Rub the leg with the olive oil. Then rub with the garlic, making sure to cover as much of the leg as possible. Then sprinkle and rub in the other spice(s). When you put the lamb in the roaster, you want it covered with oil and herbs, both for the flavor and to keep it moist.
Put lamb in oven for 1/2 hour. It will snap and sizzle, so you might want to ventilate the kitchen for a while. (No, I don’t put foil over the meat.) Then turn the heat down to 350 and cook for 30 min/pound. After two hours I check the temperature. Many lamb legs now come with a timer but thus far they have been untrustworthy, and I find that a four pound piece of meat takes about two and a half hours total to reach 150-160 degrees at the thickest point. I like my lamb on the rare side of medium, and 150 degrees seems to be about right. I also live at 3800′ above sea level, so you may do better with a shorter cooking time.
Once the meat is at the right temp, remove from the oven and let rest for five minutes or so. Remove the string net (also messy), slice, and serve with a mild side. Some people like mint sauce (traditional) or lingonberry (for game – use sparingly).