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One of these things is not like the other, is what I thought to myself the first time I noticed Lamb with Cumin on the menu at New Taste of Asia, a now long-gone Sichuan restaurant in Brookline, MA. It was like watching that episode of Full House when Steve Urkel suddenly shows up to lend Danny and Uncle Jesse life advice, or seeing a couch suddenly materialize in the center of a cricket field. Something just didn't register, didn't make sense.
What sort of madness is this? Lamb? Cumin? At a Chinese restaurant? What came out of the kitchen when I ordered it was transcendent. Tender strips of thinly sliced lamb coated in a lightly crunchy, intensely flavored crust, fried until it was almost dry on the exterior, yet still housing a juicy core.
The aroma had the distinct musky scent of cumin, but was bound together with other, more complex flavors. A hint of Sichuan peppercorns were there—my mouth became ever so slightly numb after the first few bites—as were a handful of dried chilis, though you'd be hard pressed to call the dish spicy. Aromatic is a better term. Garlic, soy, and a big, fat bed of cilantro.
At the time, even Sichuan cuisine was relatively new to me—braised beef with chilis, numbing-hot chicken, tofu doused in chili oil—and New Taste was known for its authenticity with ingredients and recipes. Yet even in that context, the lamb dish still stuck out as something different, exotic, lacking the typical ginger and sugar of Chinese-American cuisine or the vinegar and heat of Sichuan. No ginger, no scallions, no sugar, no wine, not even a sauce.
Since then, I started seeing it pop up in one form or another on menus all over Boston and New york, usually in Sichuan restaurants, quite often under a separate header on the menu titled "Northern Specialties," or the like.
Turns out that the dish is not exactly a Sichuan staple, at least not until recently. As Northern implies, it's a dish that originates in Xinjiang, China's vast Northwestern landlocked province that borders Mongolia, Russia, Kazakhstan, Pakistan, and Kyrgyzstan, among others. One of the most ethnically diverse regions in the country, until the latter half of this century, the dominant group was the Turkic Uyghur, and it is from their Muslim cuisine that the dish originates. Since then, it's been brought deeper into China, becoming a staple of street cart vendors throughout Northern China, and even to muslim restaurants in major cities in the South and the East. I even spied it on a menu in Hong Kong a couple years ago.
Its cultural background explains its unique flavor profile, but what about cooking technique? It's clearly not a standard stir-fry. The pieces of lamb come out far dryer, with a sort of crust around them. It seems to me to be more closely tied to the Sichuan method of dry-frying, a technique in which meat is par-cooked in oil until the exterior is crunchy, chewy, and dry before being re-incorporated into the dish. At least, it must be somewhere between dry-frying and standard stir-frying.
In Jeffrey Alford and Naomi Duguid's Beyond The Great Wall, a beautiful book about the cuisines of Northern China and Mongolia, they offer a version that they were served in a stall near the ancient Silk Road. They start by toasting cumin and garlic, adding sliced lamb, then cooking the whole thing down with bean sprouts and greens. Mark Bittman published a similar recipe in the 2008 New York Times Diner's journal using cubed lamb and scallions. Neither one achieved quite the level of crusty flavor I was looking for in my lamb, but both offered the good advice to use whole cumin seed and to take the time to toast them beforehand.
Toasting whole spices not only volatilizes some of their aromas, making your kitchen smell great, but it actually physically transforms some of them, effecting chemical reactions that trigger the formation of hundreds of new, aromatic compounds. Tasted side by side, the difference is undeniable. Using whole cumin (and in my version, Sichuan peppercorn) is essential—cumin powder can't be toasted properly, and it doesn't give you the nice little crunchy bits that make the dish interesting to eat.
I tried cooking it using several methods, and the one that I found worked best was to stir fry it with just a bit more oil than I'd typically use so that rather than simply searing, the meat was essentially shallow-frying. Doing this all in a wok set over a coal grill allowed me the necessary heat output to cook the lamb and vegetables all in one go. That said, even on the stovetop, it works out great, provided you cook in batches and allow the wok to reheat between each addition.
To get the cumin flavor into the lamb, I toast the spices first, then combine them along with some garlic (minced on a microplane grater), and a touch of soy sauce—not much—into a paste which I then rub all over the lamb. As the lamb cooks, this paste dehydrates and chars, forming the crunchy, flavorful crust I was looking for.
Only thing left was to add a bit of heat and aroma in the form of dried roasted chilis, and a couple of carefully chosen vegetables. While the sprouts and greens that Alford/Duguid use are nice, I prefer the sweetness of onions—another vegetable brought to China from Eurasia via the silk road—and a few stalks of crunchy celery.
And unless your spouse really really loves cumin and garlic—and mine doesn't—I suggest you make this dish while they are out of the house and not expected to return for the several days it takes for the awesome aromas to clear out.
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About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.