Wash artichokes by plunging them up and down in cold water. Cut off stem ends, and trim 1/2 inch from top of each artichoke. Remove any loose bottom leaves. With scissors, trim away one-fourth of each outer leaf. Rub tops and edges of leaves with lemon wedges to prevent discoloration.
Place artichokes in a Dutch oven; add water to depth of 2 inches. Bring to a boil; cover, reduce heat, and simmer 30 minutes or until artichokes are tender. Drain; let cool. Spread leaves apart; scrape out fuzzy thistle centers (chokes) with a spoon, and discard. Set artichokes aside.
Combine chicken and next 7 ingredients in a large bowl; stir well. Spoon chicken mixture evenly into artichoke cavities. Arrange artichokes in a 13- x 9- x 2-inch baking dish. Pour broth into dish around artichokes. Cover and bake at 350° for 30 minutes. Uncover and sprinkle with cheese; bake 10 additional minutes or until cheese melts. Sprinkle with 1/4 cup parsley, and serve with lemon slices, if desired.