Step 1

Place a 9x13-inch pan on the bottom rack of the oven and fill it halfway with water. Place your other rack in the center of the oven. Preheat the oven to 325 degrees F. Spray a 9-inch springform pan with nonstick spray, then line the bottom of the pan with parchment, then spray again. In a large bowl, use an electric mixer to blend the cream cheese until it is smooth and creamy, 1 to 2 minutes. Mix in the sugar and salt and blend for 2 minutes, scraping down the sides of the bowl to make sure all is mixed in. Add the eggs, one at a time, blending after each addition. Finally, mix in the sour cream, whipping cream and vanilla. Mix until smooth. Pour the batter into the prepared pan. Set the pan on the middle rack in the pre-heated oven. Bake the cheesecake for 45 minutes. It should be set to the touch and not jiggly. Remove the cheesecake from the oven and let it cool on a wire rack for at least an hour. When it has cooled, place the pan into the freezer and let the cheesecake freeze completely (4 to 5 hours or overnight).

Step 2

Preheat the oven to 350 degrees F. Spray two 9-inch round cake pans and line the bottoms with parchment; spray the parchment as well. In a medium bowl, whisk together the flour, baking powder, and salt. In a large glass bowl, use an electric mixer to beat together the sugar and butter on medium speed until combined, 1 to 2 minutes. Add the eggs and beat well, scraping down sides of bowl as necessary. Reduce the speed to low and gradually add the flour mixture, beating until combined. Add the milk and vanilla and beat until just combined. Scoop half of the batter into another glass bowl and use gel paste (classic red and royal blue) to color the each half a deep hue. Scrape the batter into each of the prepared pans. Bake until firm to touch and a toothpick inserted into centers comes out clean, 25 to 30 minutes. Let cakes cool in pans on wire racks 15 minutes. Turn out cakes onto racks to cool completely.

Step 3

In a large bowl, use an electric mixer to beat together the butter and cream cheese on medium-high speed until pale and creamy, about 1 minute. Reduce speed to medium. Add the powdered sugar 1 cup at a time, beating well after each addition. Add the salt, 3 tablespoons milk, and vanilla and beat until fluffy, about 3 minutes. Add an additional tablespoon of milk if you'd like the frosting to be more creamy.

Step 4

Place the red cake layer on a cake plate and spread a small amount of frosting on top. Remove the (frozen) cheesecake from the pan and place the cheesecake layer on top of the red layer (be sure to measure it and make sure that it fits on top... you may need to place it on a cutting board and shave off some of the edge with a sharp knife to match the size of the cake layer). Spread a small amount of the frosting on top of the cheesecake layer. Add the blue layer on top. Scoop some frosting on top of the blue layer and cover the entire cake in a VERY THIN LAYER of frosting (you're just doing a "crumb coat.") Then place the cake in the freezer for a few minutes, just until the cake and frosting are a little bit firm. Then add the remaining frosting to the top of the cake, spread across the top evenly and down the sides. Sprinkle festive sprinkles on top, if desired. The cake should be refrigerated until ready to serve.