Ingredients

  • 2 garlic cloves, smashed
  • 1/2 small onion, thinly sliced
  • 3/4 cup coarsely chopped fresh mint
  • 3 tablespoons coarsely chopped fresh savory or thyme
  • 3 tablespoons extra-virgin olive oil
  • Finely grated zest and juice of 2 medium lemons
  • 1 teaspoon cumin seeds, toasted
  • 1 (7- to 8-pound) leg of lamb, boned and trimmed of all fat (but not tied)
  • 1 tablespoon vegetable oil
  • 1 large garlic clove
  • 1 teaspoon kosher salt
  • 2 cups loosely packed fresh mint leaves
  • 2 large egg yolks
  • 1 1/4 cups canola oil
  • 2 tablespoons fresh lemon juice
  • 2 tablespoons warm water
  • Special equipment: kitchen string; a large roasting pan with a wire rack

Method

  • Stir together garlic, onion, mint, savory, olive oil, lemon zest and juice, and cumin in a baking dish just large enough to hold lamb.
  • Put lamb in dish and turn to coat, rubbing marinade into entire surface.
  • Marinate lamb, covered and chilled, turning once or twice, at least 12 hours.
  • Mash garlic to a paste with kosher salt using a mortar and pestle (or mince and mash with a large heavy knife), then add 1 cup mint and pound to a paste (or mince and mash with knife).
  • Transfer to a bowl and whisk in yolks, then add half of oil, 1 to 2 teaspoons at a time, whisking constantly.
  • Whisk in lemon juice, then slowly add remaining oil, whisking.
  • Season with salt and pepper and stir in warm water.
  • Working with several leaves at a time, stack remaining cup mint leaves, then roll up and thinly slice crosswise to make a chiffonade (thin strips).
  • Stir mint into aioli and chill until ready to use.
  • Preheat oven to 400F.
  • Wipe all of marinade from lamb and discard.
  • Pat lamb dry and season both sides generously with salt and pepper.
  • Arrange lamb, boned side up, on a work surface and, beginning with a long side, roll up as tightly as possible and tie tightly with string.
  • Heat vegetable oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then brown lamb on all sides, about 8 minutes.
  • Transfer to rack set in roasting pan and roast in middle of oven until an instant-read thermometer inserted into lamb reads an average of 140F for medium-rare (test in several places, as different muscles cook at different speeds; temperatures should range from 120 to 160F), 40 to 60 minutes.
  • Let stand 15 to 20 minutes before slicing.
  • Serve lamb with aioli.