I recently came clean about something I've been hiding for a long time. Despite working for a site that has long promoted cooking techniques like sous vide and the reverse sear—methods that prioritize a perfect edge-to-edge gradient of doneness—I confessed that I have other priorities when it comes to cooking meat. I'm willing to accept a small rim of overcooked meat on a beef steak if it means I can get a more robust sear—and therefore more deep flavor—on the exterior.
But if I'm ambivalent about prioritizing even doneness on steak, I'm a full-fledged skeptic when it comes to lamb. There's plenty to be said for wanting to minimize the gradient on beef, since cuts like strip steaks, ribeyes, and tenderloins dry out in unappetizing ways as soon as they overheat; there's good reason not to want that. But lamb? Lamb is an entirely different beast, and its meat and fat are delicious in different ways.
Opinions about how cooked a piece of meat should be are, of course, exactly that. There's no right answer, but that doesn't mean there aren't objective differences depending on the animal and cut. Beef has some fairly clear divisions. The more tender, quick-cooking cuts that we eat as steak become tough and dry as they surpass medium-well, while the collagen-rich and fatty muscles that we use for braises and stews require long cooking to be delicious. Only a few parts of the cow straddle both lines (short ribs, if handled correctly, being one).
Lamb is different. Like duck, it's one of those magical animals that remains delicious at a range of temperatures all the way up to well done, more or less regardless of the cut. That isn't to say some parts of the animal aren't slightly better one way or another: If I have a rack of lamb or duck breast on their own, I definitely don't want them cooked to well done. But if you've ever eaten a whole roast duck or lamb, you'll know that the breast and loins remain tasty even when they do cross into the fully-cooked zone.
This is partly because of their wonderfully delicious fat, which gets better the more it sizzles and melts. It's also because of the ratio of fat to meat. Since lamb and duck are smaller than cows, nearly every bite of a lamb chop or duck breast can have a healthy rim of juicy fat attached, something that's not true of beef.
Too often, I've eaten lamb chops that have prioritized a perfectly even medium-rare from edge to edge, and it's probably one of my least favorite ways to eat it. The fat hasn't rendered and basted the meat enough, and the meat retains a minerally chew that can make me gag. I'll take a more sizzling rack of lamb any day over that. Since the only methods we have on Serious Eats right now lean in the direction of perfectly even, medium-rare meat, I figured it was time to deliver options for those who are after what I'm after.*
Reverse-Sear or Pan-Roast?
This might seem like a strange question to ask given that I've just made it clear that methods that prioritize an even gradient, of which the reverse sear** is one, aren't my favorite for lamb. But a rack of lamb is small, which means that any searing step will give you some kind of gradient—the heat penetrates too quickly to avoid it. For people who don't want a gradient, they need another method, like cooking the lamb in a water bath, whether sous vide or using the cooler trick. For me, though, it means the reverse-sear is an option worth considering.
**For those not familiar, the reverse sear works by slowly heating the meat in a low oven until it reaches your target temperate in the center; then the meat is seared using high heat to crisp and brown the exterior.
I compared racks that I cooked using the reverse sear against ones that I butter-basted in a pan on the stovetop the whole time. I also tested various methods for finishing a reverse-seared rack, including in a pan, in a very hot 500°F oven, and under the broiler. The oven and broiler methods were the worst. In the case of the hot oven, it didn't get nearly enough of a sear on the meat; if I'd left it in longer, though, I definitely would've been left with unpleasantly dry, tough meat. The broiler method was even worse—it browned so unevenly that the lamb was burned in some spots and under-seared in others.
When finished in a hot pan, a reverse-seared rack of lamb comes out pretty well, maybe not by the standards of what the reverse sear does on a larger piece of meat, but certainly by my lamb-eating criteria.
Still, I'd rather eat a rack of lamb that's been pan-roasted from start to finish, turning it frequently and basting it with garlic-and-herb-infused butter the whole time until it's done. The flavor is deeper, richer, roastier, and the lamb is gorgeous, a rosy pink in the center, but with fat up around the ribs that's dripping with juices. For me, it's perfection.
Do You Need to Dry-Brine a Rack of Lamb?
Generally speaking, meat does better when it's dry-brined before cooking. Dry brining merely means seasoning the meat all over with salt, then letting it rest uncovered in the fridge long enough for the salt to draw out moisture from the meat and then reabsorb it; by the time you cook the meat, the surface should be dry to the touch. The resulting meat not only retains juices better after this process, but the dry exterior browns more quickly.
To my surprise, I didn't notice much of a difference between my dry-brined and un-brined lamb in my tests. This makes some sense in the case of the reverse-sear, since the meat has plenty of time to dry off in the low oven before the searing step, but it was more of a surprise for the pan-roasted version.
One explanation has to do with the fat cap on the top side of the rack and membrane on the rib side—it's possible these coverings prevent the salt from penetrating the muscle tissue as successfully, minimizing the effect of the brine. Still, there's no harm in doing the dry brine step if you have the time, so I'd say do it if you can, but don't sweat it if you can't.
Should You Score Lamb Fat?
Some recipes tell you to score the fat cap that covers the meaty side of the lamb as one does with the skin on a duck breast. The incisions increase the surface area of the fat exposed to the heat, which renders the fat more quickly and fully.
I tried it both ways and, at least with the lamb I was using, didn't find much of an effect. Frankly, I love hot lamb fat so much that I don't care if there's a little more of it. It's worth noting, though, that the lamb I was testing didn't have a cap that fully covered the loin, as some do, and the cap it did have wasn't too thick. I'd be much more inclined to score the fat if it were on the thicker, fuller side.
In the end, though, the real lesson is that if you roast the racks more deeply, there’s less need to "deal" with the fat in the first place, because it’s going to be perfect.