In mixing bowl, combine flour, sugar, baking powder, cinnamon and salt. In another bowl, beat egg yolks slightly. Beat in milk and cooking oil. Add egg yolk mixture to flour mixture all at once. Stir just until combined, but still slightly lumpy. Stir in chopped apple. In small bowl, beat egg whites until stiff peaks form (peaks will stand straight.)?Gently fold beaten egg whites into batter, leaving a few fluffs of egg white. DO NOT OVERMIX. Pour some of the batter onto grids of a preheated lightly greased waffle baker. Close lid quickly. Do not open during baking. Bake according to manufacturer’s directions.??When done, use a fork to lift waffle off grid. Repeat with remaining batter. Serve with warm maple syrup and butter. Top with fresh fruit, if you like.?