Roast Leg of Lamb with Mint Aioli
For the Lamb:
2 garlic cloves, smashed
1/2 small onion, thinly sliced
3/4 cup coarsely chopped fresh mint
3 Tbs. coarsely chopped fresh savory or thyme
3 Tbs. extra-virgin olive oil
Finely grated zest and juice of 2 medium lemons
1 tsp. cumin seeds, toasted
1 (7-8 lb.) leg of lamb, boned and
trimmed of all fat (but not tied)
1 Tbs. vegetable oil
For the Aioli:
1 large garlic clove
1 tsp. kosher salt
2 cups loosely packed fresh mint leaves
2 large egg yolks
1 1/4 cups canola oil
2 Tbs. fresh lemon juice
2 Tbs. warm water
Marinate Lamb: 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.
Make Aioli: 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. 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.
Roast Lamb: Preheat oven to 400 degrees. 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 140 degrees for medium-rare (test in several places, as different muscles cook at different speeds; temperatures should range from 120 to 160 degrees), 40 to 60 minutes. Let stand 15 to 20 minutes before slicing. Serve lamb with Aioli.