Red Velvet Cheesecake with Buttercream Frosting

Preheat oven to 350 degrees F (175 degrees C). Place a pan of hot water in the bottom of the oven.

Line two 9-inch springform pans with aluminum foil; grease with cooking spray.

Beat cream cheese in a bowl with an electric mixer until smooth, about 3 minutes. Add 1 1/2 cup white sugar and cornstarch; beat until smooth. Add 1 tablespoon vanilla extract. Beat in 2 eggs and 2 egg whites, 2 at a time, until batter is creamy. Add heavy cream; beat just until batter is free of lumps and fluffy.

Divide batter between the prepared pans.

Bake in the preheated oven until edges appear set, about 40 minutes. Turn off oven; leave cheesecakes inside for 1 to 2 hours. Chill until firm, at least 4 hours or overnight.

Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9-inch round cake pan.

Whisk buttermilk and 3/4 teaspoon vanilla extract together in a small bowl.

Whisk flour, cocoa powder, cinnamon, baking soda, and salt together in a separate bowl.

Beat 1 1/4 cup white sugar and oil with an electric mixer until creamy. Whisk in 2 eggs, one at a time. Add vinegar and red food coloring; beat well. Beat in flour mixture in 3 additions, alternating with buttermilk mixture, until batter is smooth. Pour batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 50 minutes. Cool for 10 to 15 minutes in the pan. Invert onto a wire rack. Cut horizontally into 2 even layers. Chill until firm, at least 4 hours to overnight.

Combine butter, shortening, and marshmallow cream in a large bowl; beat with an electric mixer on high speed until creamy. Add 1 1/2 teaspoon vanilla extract; beat until light and fluffy. Add confectioners' sugar 1 cup at a time, beating until frosting is smooth.

Place 1 cake layer on a serving plate. Spread a thin layer of frosting on top; stack 1 cheesecake layer over cake. Spread a thin layer of frosting over cheesecake; repeat layers. Spread frosting over top and sides of cake.