Rub entire leg of lamb with olive oil. Cut one inch slits throughout entire leg and insert garlic cloves. In a small bowl combine salt, pepper and oregano and insert small amounts of mixture in the slots along with the garlic. Place in large baking dish fat side up and drizzle with lemon juice. Add additional salt, pepper and oregano on the top of leg and sprinkle with rosemary.
Peel potatoes and place around the leg. Add two cups of water in the base of dish. Place in preheated 325 degree oven and bake for 5-6 hours (oven temperatures may vary) until fat side is a crispy brown. Baste occasionally during baking. The juice is so well flavored that you may serve with lamb in a gravy boat. Just add a little water and heat.
