In a large dutch oven, heat oil. Brown lamb and onions. Stir in flour; mix well. Gradually, add broth. Bring to a boil, stirring to remove browned bits from pan. Add carrots, leeks, 1 tablespoon of parsley, bay leaf, rosemary, thyme, salt and pepper. Spoon into a greased 3 quart casserole. Cover with potatoes and dot with butter. Bake at 350 degrees for 1 1/2-2 hours or until the meat is tender and the potatoes are golden brown. Garnish with remaining parsley. Yield: 6-8 servings.