1. Make the Cheesecake Layer (Day 1):2. Preheat oven to 325°F (163°C). Grease a 9-inch springform pan.3. In a large bowl, beat the cream cheese and sugar until smooth. Add the eggs one at a time, mixing on low. Stir in the sour cream and vanilla.4. Pour batter into the pan. Wrap the pan tightly in aluminum foil. Place in a large roasting pan. Pour hot water into the roasting pan to come 1-inch up the side of the springform pan.5. Bake for 60-70 minutes, until the edges are set and the center is almost set (still jiggly).6. Turn off the oven and let the cheesecake sit in the cooling oven with the door cracked for 1 hour.7. Remove, let cool to room temperature, then chill in the refrigerator overnight.8. 9. Make the Red Velvet Cake Layers (Day 2):10. Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans (not springform).11. In a large bowl, whisk the flour, sugar, baking soda, salt, and cocoa powder.12. In a separate bowl, whisk the oil, buttermilk, eggs, red food coloring, vinegar, and vanilla.13. Pour the wet ingredients into the dry ingredients and whisk until just combined. Do not overmix.14. Divide the batter between the two 9-inch pans. Bake for 30-35 minutes, or until a toothpick comes out clean.15. Cool layers in the pans for 15 minutes, then invert onto a wire rack to cool completely.16. 17. Make the Frosting (Day 2):18. In a large bowl, beat the room-temperature cream cheese and butter until smooth.19. On low speed, gradually add the sifted powdered sugar. Add the vanilla and salt.20. Beat on medium-high for 2-3 minutes until light and fluffy.21. 22. Assemble the Cake (Day 2):23. Place one red velvet cake layer on a serving platter.24. Carefully remove the chilled cheesecake from the springform pan and place it on top of the cake layer.25. Place the second red velvet cake layer on top of the cheesecake.26. Apply a thin crumb coat of frosting over the entire cake. Chill for 30 minutes.27. Frost the cake with the remaining frosting. Chill until ready to serve.