feel this way should be thankful—it makes cooking roasts
very easy. Just bang it into a hot oven (around 400°F should
do) and roast until the very center reaches the desired
temperature.
But if you, like me, want your lamb evenly cooked from
edges to center, the best thing to do is slow-roast it, just as
when cooking prime rib (see Perfect Roast Prime Rib, here):
Place it in a 200°F oven until it is within a few degrees of
your desired serving temperature (use that thermometer!).
Remove it, crank the oven up as far as it will go, and let it
heat up, then throw the lamb back in for about 15 minutes to
crisp up the well-rendered fat layer on the exterior.
Q: Do I have to let my lamb rest just like beef?
Just as with a steak or a beef roast, lamb muscles tighten
when they’re hot. As they loosen up during resting, their
ability to retain their juices increases. This means that more
juice ends up in your meat and less on the cutting board.
Allow lamb roasted entirely at a high temperature to rest for
at least 20 minutes after removing it from the oven, and
meat roasted low-and-slow to rest for at least 10 minutes.