Kosher salt and freshly ground black pepper 8 sprigs fresh rosemary or thyme (optional) 2 medium shallots, roughly chopped (optional) 4 medium cloves garlic, roughly chopped (optional) 1 tablespoon vegetable oil 1 tablespoon butter 1 recipe Salsa Verde (recipe follows) Cook the lamb in your cooler as directed here, using 133°F water for medium-rare, or 143°F water for medium, for at least 45 minutes, and up to 3 hours After removing the lamb from the bags, discard any aromatics and pat the lamb dry with paper towels Heat the oil and butter in a 12-inch heavy-bottomed stainless steel or cast-iron skillet over high heat until smoking Add the lamb to the skillet fat side down and sear until well browned on all sides, turning with tongs, about minutes total (for particularly large racks, sear the lamb in two batches, tenting the first batch with foil after searing to retain the heat) Transfer the seared lamb to a platter, tent with foil, and allow to rest for 5 minutes, then carve and serve with the salsa verde Salsa Verde MAKES ABOUT 1 CUP ẳ cup capers, drained ẳ cup finely minced fresh parsley ắ cup extra-virgin olive oil 1 tablespoon honey 4 anchovy fillets, finely minced 1 medium clove garlic, minced or grated on a Microplane (about 1 teaspoon) Kosher salt and freshly ground black pepper Press the capers between a double layer of paper towels to remove excess moisture Finely chop and transfer to a large bowl Add parsley, olive oil, honey, anchovies, and garlic and whisk to combine Season to taste with salt and pepper ... 4 anchovy fillets, finely minced 1 medium clove garlic, minced or grated on a Microplane (about 1 teaspoon) Kosher salt and freshly ground black pepper Press the capers between a double layer of paper towels to remove excess moisture