1 can (18.25 ounces) red velvet cake mix (like Duncan Hines®)
1 ¼ water
1/3 cup vegetable oil
2 (8 oz) packages cream cheese, softened, divided
(2 cup) white sugar
1 egg white
1/3 cup unsalted butter, softened
2 cups icing sugar
1 teaspoon vanilla extract
1 tablespoon milk
Preheat oven 350 degrees F (175 degrees C). Spraying 9 * 13-inch baking dish with cooking spray.
Mix cake mixture, water, oil and 3 eggs in a bowl with an electric mixer until smooth. Spread half of the dough evenly on the bottom of the prepared mold.
Beat together 1 1/2 packets of cream cheese, white sugar, and egg white in a separate bowl with an electric mixer until smooth. Place spoonfuls of cream cheese mixture in cake dough in a pan. Pour the remaining batter over the top, spreading evenly to completely cover the cream cheese mixture.
Bake in preheated oven until the top is firm and no longer shines, about 40 minutes. Let the cake cool completely, for at least 40 minutes.
Combine the remaining cream cheese and butter in the bowl. Add icing sugar; stir until smooth. Stir in vanilla extract until smooth. Add milk; stir until smooth. Spread frosting on the cooled cake.