To prepare topping: Place cream cheese in a small mixing bowl and beat with an electric mixer until smooth and creamy. Add sugar and beat until smooth. Add egg, flour, yogurt and vanilla; beat until well blended.
To prepare brownie layer: Whisk whole-wheat flour, cocoa and salt in a bowl. Place egg, egg whites and brown sugar in a large bowl and beat with the electric mixer on medium speed until smooth. Add oil, coffee (or tea) and vanilla; beat until well blended. Add the dry ingredients and beat on low speed just until well blended, stopping once to scrape down the sides