Preheat your oven to 325°F (163°C) and prepare a 9-inch springform pan by greasing it with butter. In a mixing bowl, beat together the cream cheese, granulated sugar, salt, eggs, sour cream, heavy whipping cream, and vanilla extract until smooth and creamy. Pour this cheesecake batter into the prepared pan and bake for 45 minutes. Once done, let it cool and freeze for at least two hours.

Increase the oven temperature to 350°F (177°C) and grease two 9-inch round cake pans. In a large bowl, combine the white cake mix, water, vegetable oil, and egg whites, mixing until just combined. Divide the batter between the prepared pans and bake for 30-35 minutes until a toothpick comes out clean. Allow the cake layers to cool in the pans for 10 minutes before transferring to wire racks.

While the cake layers are cooling, prepare the frosting by beating the softened salted butter until creamy. Gradually add powdered sugar and mix until well combined. Pour in vanilla extract and a splash of heavy whipping cream, beating until smooth.

Layer one cooled chocolate chip cake on a cake stand or plate. Spread cream cheese frosting on top, place the frozen cheesecake layer over the frosting, and frost the cheesecake layer. Top with the second chocolate chip cake layer and frost the entire cake generously with the remaining cream cheese frosting.

Sprinkle extra miniature chocolate chips over the cake for garnish. Refrigerate for at least 2 hours to set nicely.