Get Ready: Preheat your oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish with non-stick spray.
Make Cake Batter: In a large bowl, prepare the chocolate cake batter exactly as directed on your cake mix box, using the eggs, water, and oil. Set it aside for a moment.
Whip Up Cheesecake Swirl: In a separate medium bowl, combine the softened cream cheese, granulated sugar, and egg white. Using an electric hand mixer, beat these ingredients on medium speed for 1-2 minutes until the mixture is beautifully smooth and well combined.
Layer the Cake: Pour half of your chocolate cake batter into the prepared baking dish and spread it evenly. Next, spoon generous dollops of the cream cheese mixture all over the cake batter. Gently swirl the cream cheese into the chocolate batter using the back of your spoon – don't overmix, just create lovely ribbons of flavor!
Add More Batter: Carefully pour the remaining chocolate cake batter over the swirled cream cheese layer, spreading it gently and evenly to cover all the cheesecake mixture.
Bake to Perfection: Bake for 35-40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let the cake cool completely on a wire rack before you even think about frosting it!
Prepare Frosting: While the cake cools, prepare the frosting. In a clean bowl, beat together the softened cream cheese and butter with an electric mixer until light and fluffy. Gradually add the powdered sugar, then mix in the vanilla extract and milk until your frosting is perfectly smooth and creamy.
Decorate & Serve: Once the cake is completely cool, spread the delicious cream cheese frosting evenly over the top. Finish by sprinkling the crushed peppermint candy canes all over for a festive touch. Slice and enjoy your delightful, homemade treat!