Combine first 4 ingredients in a large mixing bowl; stir well. Combine 4 egg whites and next 3 ingredients in a small bowl; add to dry ingredients, stirring well. Spread batter in an 8-inch square pan coated with cooking spray.
Combine cream cheese and remaining ingredients in a medium bowl. Beat at low speed of an electric mixer until smooth. Spoon cream cheese mixture by tablespoonfuls over cocoa mixture. Cut through cream cheese and cocoa mixtures with a knife to create a marbled effect. Bake at 350° for 22 minutes or until wooden pick inserted in center comes out almost clean. Let cool in pan on a wire rack. Cut into bars.