Spice-Rubbed Leg of Lamb

Chop the onion, parsley, garlic, and spices in a food processor until smooth. Add the lemon juice and butter; beat until smooth.Transfer the lamb to a large, shallow skillet. Pour the marinade over the lamb and turn it over several times to coat it. Cover with plastic wrap and refrigerate overnight.Place the grill rack in the bottom third of the oven and preheat the oven to 450°F. Remove the lamb from the marinade; wipe off any excess. Place the lamb on a rack in a shallow baking dish and bake for 20 minutes; reduce the oven temperature to 325 °F. Bake the lamb until an instant-read thermometer inserted into the thickest part of the meat shows 140 °F (for medium-deep-fried meat), for 1 hour and 15 minutes.Transfer the meat to a cutting board; let stand for 20 minutes. Cut the meat so that the tip of the lamb bone is facing you. Slice away from you and down, keeping the knife parallel to the bone and turning the lamb over as you cut. Serve with mint pesto.