Preheat oven to 400 degrees. Make small slits just large enough for garlic slivers evenly in leg and insert the slivers. Rub all over with lemon juice and pat rosemary and pepper evenly over surface. Sprinkle with salt to taste.
Place leg of lamb in a roasting pan and put it in the oven. Immediately reduce heat to 350 degrees. Roast for 1 1/2 hours for medium rare. (I use meat thermometer inserted in thickest portion to make sure roast's internal temperature reaches about 185 degrees.) Let stand 10 minutes before carving. 6-8 portions.
