1. Place the butterflied leg of lamb on a cutting board. It should be a large, flat piece of meat of uniform thickness. If necessary, cover with plastic wrap and pound lightly the flat side of a meat mallet.
2. For marinade combine the 3 tablespoons oil, 2 garlic cloves, the red pepper flakes, orange peel, fennel seeds, cardamom and ginger in a small glass bowl. Rub with marinade to coat all sides. Transfer lamb to a heavy-duty plastic storage bag; seal bag. Marinate lamb in the refrigerator 2 to 12 hours.
3. Meanwhile, for tapenade combine 2 tablespoons oil and 3 cloves garlic in small skillet. Cook garlic over medium heat, stirring until fragrant, 1 minute. Add olives, capers, and anchovies; cook until anchovies begin to break apart and capers color slightly, 3 to 4 minutes more. Transfer olive mixture to food processor. Pulsing machine several times on and off, process mixture until all ingredients are blended but still slightly chunky. Transfer tapenade to a small glass bowl.
4. Melt butter in large skillet over medium heat. Add bread crumbs and rosemary; cook, stirring often, until bread crumbs brown lightly, 2 to 3 minutes. Remove skillet from heat; stir parsley into the crumbs. Set aside.
5. Heat broiler. Transfer lamb to the bottom of broiler pan and lay flat. Broil lamb 4 inches from heat source, until top is well browned, 10 to 12 minutes. Reduce oven temperature to 400 degrees F. Transfer broiler pan to center oven rack and roast lamb 20 minutes. Remove lamb from oven. Spread tapenade evenly over top of lamb. Sprinkle feta cheese over tapenade, then bread crumbs over feta cheese. Return lamb to oven and roast 7 to 8 minutes more, until meat registers 140 degrees F on instant-read thermometer when inserted in thickest portion of lamb (for medium-rare). Transfer lamb to a cutting board, let stand 5 minutes before slicing. Thinly slice lamb, then arrange on a large serving platter. Serve with asparagus and potatoes, if desired. Makes 6 to 8 servings.