Preheat oven to 350 degrees F. Grease a 9×13-inch baking dish with non-stick spray. Set aside.
Prepare chocolate cake batter, according to package directions. Set aside.
In a separate bowl, mix together the softened cream cheese, sugar and egg white. Beat together with an electric hand mixer, on medium speed, for 1 to 2 minutes or until combined and smooth.
Pour only half of the chocolate cake batter into the prepared baking dish. Spread out evenly. Then take the cream cheese mixture and drop spoonfuls all over the batter in the pan. Take the back of the spoon and swirl the cream cheese mixture all over the top of the cake batter.
Pour the remaining cake batter all over the top of the cream cheese mixture. Carefully, spread the cake batter over the top evenly. Covering all of the cream cheese.
Bake for 35 to 40 minutes or until a tooth-pick inserted in center comes out clean. Let cake cool completely before frosting.