"A favorite recently discovered recipe. Guests, family, friends will love it! Seems fancy, but actually easy to make starting with store-bought cake mix and using staple ingredients usually already in the house. Because of the cheesecake filling, this cake must be kept refrigerated."
Preheat oven to 350 degrees F (175 degrees C). Coat a 9x13-inch baking pan with cooking spray.
Blend cake mix, water, oil, and 3 eggs in a bowl using an electric mixer until smooth. Spread half the batter evenly into the bottom of the prepared pan.
Beat 1 1/2 packages cream cheese, white sugar, and egg white together in a separate bowl using an electric mixer until smooth. Drop spoonfuls of cream cheese mixture into the cake batter in the pan. Pour the remaining batter on top, spreading evenly to cover the cream cheese mixture completely.
Bake in the preheated oven until top is firm and no longer shiny, about 40 minutes. Let cake cool completely, at least 40 minutes.
Combine remaining cream cheese and butter in a bowl. Add confectioners' sugar; mix until smooth. Stir in vanilla extract until combined. Add milk; mix until smooth. Spread icing over the cooled cake.