Combine the ingredients for the marinade in a large plastic freezer bag. Add the lamb and seal the bag. Shake to evenly distribute the marinade over the lamb. Refrigerate for 8 hours, turning occasionally.
Preheat the oven to 400?F.
Remove the lamb from the marinade and wash quickly under running water to remove most of the marinade. Pat dry and season with 2 teaspoons salt and 1/2 teaspoon black pepper on all sides. Spread the lamb, smooth side down, on a large baking sheet and set aside.
Combine the bread crumbs, olives, 1/4 cup olive oil, 1 tablespoon lemon juice, the pine nuts, marjoram, mint, garlic, 1 teaspoon salt, 3/4 teaspoon black pepper, and the lemon zest in the bowl of a food processor. Pulse 2 to 3 times. Do not puree. Set the stuffing aside.
Combine the remaining 1/2 cup olive oil, 2 tablespoons lemon juice, 1 teaspoon salt, and 1/2 teaspoon black pepper in a medium bowl and whisk to blend. Set this sauce aside for basting.
Spread the olive mixture evenly over the lamb. Starting at 1 long side, roll the lamb up tightly. Tie the rolled lamb at several places with kitchen string to hold its shape. Brush the outside of the lamb liberally with the basting sauce; reserve the remainder.
Roast the lamb until an instant-read thermometer inserted in the center registers 140?F for medium rare, about 1 hour and 30 minutes. Brush occasionally with the remaining basting sauce. Let stand 15 minutes. Slice the lamb and serve warm or at room temperature.
Makes 8 to 10 servings
Note: The cooking time will vary depending on the thickness of the meat. Start checking the temperature at 1 hour and don't forget that the meat will continue to cook once removed from the oven. Also, don't forget those tasty bits on the baking sheet. These can be spooned over individual slices of lamb as a sauce.