Step 1: Prepare the Cheesecake Layer

1. Preheat your oven to 325°F (163°C).
2. Line a 9-inch springform pan with parchment paper and grease the sides.
3. In a large bowl, beat cream cheese and sugar until smooth.
4. Add eggs one at a time, mixing until fully combined.
5. Stir in vanilla extract and sour cream, then mix until smooth.
6. Pour the cheesecake batter into the prepared pan and bake for 30-35 minutes, until the center is just set.
7. Allow to cool completely, then refrigerate for at least 2 hours.

Step 2: Make the Red Velvet Cake

1. Preheat your oven to 350°F (175°C). Grease and flour a 9-inch cake pan.
2. In a bowl, whisk together flour, sugar, baking soda, cocoa powder, and salt.
3. In another bowl, mix vegetable oil, buttermilk, eggs, vanilla, vinegar, and red food coloring.
4. Gradually mix the dry ingredients into the wet ingredients until fully combined.
5. Pour the batter into the prepared pan and bake for 25-30 minutes, or until a toothpick comes out clean.
6. Let the cake cool completely.

Step 3: Prepare the Cream Cheese Frosting

1. Beat cream cheese and butter together until smooth and fluffy.
2. Gradually add powdered sugar and mix until well combined.
3. Stir in vanilla extract and mix until creamy.

Step 4: Assemble the Red Velvet Cheesecake

1. Place the red velvet cake layer on a serving plate.
2. Carefully place the cheesecake layer on top of the cake.
3. Spread the cream cheese frosting evenly over the top and sides.
4. Optional: Garnish with red velvet cake crumbs, chocolate shavings, or whipped cream.