Recipe: Lamb Sirloin with Pommes Boulangère

From Rob Levitt of Butch­er & Larder. Serves 2 gen­er­ous­ly.

Some­times the clas­sics are best. The sto­ry behind this dish is that, in the old days, when there was a bak­ery in every town (in France), the towns­folk would make this pota­to dish along with a leg of lamb. On their way to do the wash, they would drop off the lamb and pota­toes with the baker’s wife who would put them in the oven. All the bak­ing was done for the day, so the lamb would roast slow­ly as the oven cooled, it’s juices and fat drip­ping onto the pan of pota­toes. When the wash was done, they’d pick up their din­ner on the way home!

While not as roman­tic, roast­ing a piece of lamb on a gratin dish full of pota­toes is real­ly fun. You can also just make the pota­toes as a side with what­ev­er stock you have on hand.

1 Lamb Sir­loin
1 pound Yukon Gold Pota­toes, peeled and sliced ¼ “ thick (a Japan­ese man­dolin works best here)
1 yel­low onion, sliced thin
1 T chopped fresh Rose­mary
1 T chopped fresh Thyme
Salt & Pep­per
1.5 C Lamb Stock (Beef, Pork or Dark Chick­en Stock will work just as well)
4 T But­ter

1. Pre­heat oven to 325 F.
2. Bring the stock to a boil, remove from heat and reserve.
3. Score a cross­hatch* into the fat on the sir­loin and sea­son lib­er­al­ly all over with salt and pep­per.
4. In a skil­let over medi­um heat, melt the but­ter. When but­ter is foamy, add the lamb fat side down, and sear gen­tly until the fat is light gold­en brown. Remove from the pan and let rest on a plate.
5. Add the onions and herbs to the pan and cook, stir­ring occa­sion­al­ly, until the onions are soft­ened and begin­ning to brown.
6. But­ter a small, shal­low casse­role or bak­ing dish. Add a lay­er of sliced pota­toes and sea­son with salt and pep­per. Add a lay­er of onions, and repeat pota­toes, salt & pep­per, onions until every­thing is in the bak­ing dish, but the top lay­er is pota­to.
7. Pour the stock over the pota­toes and place the seared lamb on top.
8. Roast until the lamb is cooked to 130 F inter­nal and the pota­toes are cooked through and ten­der, about 30–45 min­utes. If the lamb fin­ish­es before the pota­toes, it ok- just remove the lamb to rest and con­tin­ue bak­ing until pota­toes are fork ten­der.

* Scor­ing is typ­i­cal­ly done to fat­ty pieces of meat because fat shrinks and can pull the meat into a ball. Scor­ing allows for even cook­ing and a pret­ti­er end prod­uct. Score the fat until you reach the mus­cle, but don’t cut into the meat.