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.