Pork butt roast is often labeled Boston butt in the supermarket. We developed this recipe with Diamond Crystal kosher salt. If using Morton kosher salt, which is denser, use only 2¼ teaspoons in step 2. Toast the cumin and coriander seeds in a dry skillet over medium heat until fragrant, 2 to 3 minutes. The seeds can be cracked in a mortar and pestle or using the bottom of a heavy skillet. The chipotle sauce is quite spicy, so use sparingly if you are sensitive to heat. Tacos árabes are traditionally served in yeasted flatbreads called pan árabe, but since pan árabe can be hard to find, we call for pitas (look for Arabic-style, which have a pocket and are thinner, as opposed to non-hollow Greek pitas) or flour tortillas. The pork can be braised and sauces can be made up to two days in advance and refrigerated.

FOR THE PORK AND ONIONS: Adjust oven rack to middle position and heat oven to 300 degrees. Trim excess fat from exterior of pork, leaving ¼-inch-thick fat cap. Slice pork against grain into ½-inch-thick slabs.

Heat 1 tablespoon oil in Dutch oven over medium heat until shimmering. Add half of onions and cook, stirring frequently, until starting to brown, 6 to 8 minutes. Add garlic, 1 tablespoon salt, cumin seeds, coriander seeds, oregano, 1 teaspoon pepper, cinnamon, and nutmeg and stir to combine. Cook until fragrant, about 1 minute. Stir in water and lime juice. Add pork, nestling into onions and liquid (pork will not be fully submerged). Increase heat to medium-high and bring to simmer. Cover pot; transfer to oven; and cook until pork is tender but paring knife inserted into pork still meets some resistance, about 1 hour, flipping meat halfway through cooking. While pork cooks, prepare both sauces and sautéed onions.

FOR THE CHIPOTLE SAUCE: Combine all ingredients in blender and process until smooth, about 30 seconds. Season with salt to taste; set aside until serving.

FOR THE YOGURT SAUCE: Place garlic in small skillet and cook over medium heat, turning occasionally, until skins are charred on both sides, 6 to 8 minutes. When cool enough to handle, peel and mince garlic. Transfer garlic to bowl and stir in yogurt, cilantro, water, lime juice, and oil. If necessary, add up to 2 tablespoons extra water so sauce is pourable. Season with salt and pepper to taste, then refrigerate until needed.

Heat remaining 1 teaspoon oil in 12-inch nonstick skillet over medium-high heat until shimmering. Add remaining half of onions, ¼ teaspoon salt, and ¼ teaspoon pepper and cook, stirring occasionally, until charred in spots but still crisp-tender, 7 to 8 minutes. Off heat, stir in thyme and set aside.

Remove pot from oven. Transfer pork to cutting board. Set Dutch oven over high heat and bring braising liquid to rapid simmer. Cook, stirring occasionally and scraping any browned bits from sides of pot, until syrupy (spatula drawn across bottom of pot should leave clean trail), 12 to 15 minutes. Off heat, return pork to Dutch oven and coat both sides of each piece with sauce.

Heat broiler. Line rimmed baking sheet with aluminum foil and top with wire rack. Arrange pork in single layer on rack and spoon about 2 teaspoons sauce over top of each piece. Broil until pork is well browned with bits of charring and crisping around edges, 5 to 7 minutes. Transfer pork to cutting board and let rest for 5 minutes, then slice each piece crosswise into ⅛-inch strips.

Transfer pork to serving platter. Serve, passing onions, yogurt sauce, chipotle sauce, pitas, cilantro sprigs, and lime wedges separately.

The Magic of the Trompo——and How to Mimic It at Home