Mash prunes; stir in oatmeal and cinnamon; set aside. Beat egg whites until frothy. Gradually add sugar, a tablespoon at a time, beating constantly until stiff and glossy. Gently fold in prune mixture. Spoon into 6 individual dishes or large serving dish. Chill several hours or until set. *NOTE: Cook Quaker Oats (quick or old fashioned, uncooked) according to package directions.