1. Prepare the Red Velvet Cake Layer

1. Preheat your oven to 350°F (175°C). Grease and line a 9-inch springform pan.
2. In a bowl, whisk flour, cocoa powder, and salt. Set aside.
3. In a large bowl, beat butter and sugar until creamy. Add sour cream, oil, and vanilla.
4. Mix in eggs one at a time. Add red food coloring and stir well.
5. Add half of the dry ingredients, then the buttermilk, then the remaining dry ingredients. Mix until just combined.
6. In a small cup, combine baking soda and vinegar—let it fizz, then fold into the batter.
7. Spread the batter into the springform pan and bake for 20–25 minutes, or until a toothpick comes out clean.
8. Let cool completely before adding the cheesecake layer.

2. Make the Oreo Cheesecake Filling

1. Beat cream cheese until smooth.
2. Add sugar and cornstarch, mixing until combined.
3. Add sour cream, vanilla, and the Oreo filling you set aside.
4. Add eggs one at a time, mixing on low speed. Do not overmix.
5. Fold in crushed and chopped Oreos.
6. Pour the cheesecake batter over the cooled red velvet layer.

3. Bake the Cheesecake

1. Wrap the outside of the springform pan in foil.
2. Place the pan into a larger roasting pan and pour in hot water halfway up the sides.
3. Bake at 325°F (160°C) for 50–60 minutes. The center should jiggle slightly.
4. Turn the oven off, crack the door open, and let the cheesecake cool inside for 1 hour.
5. Refrigerate for at least 4 hours or overnight.

4. Prepare the Ganache Topping

1. Heat heavy cream until steaming.
2. Pour over the chocolate chips and let sit for 2–3 minutes.
3. Stir until smooth and glossy.
4. Spread over the chilled cheesecake.

5. Decorate the Cheesecake

1. Pipe swirls of cream cheese frosting around the edges.
2. Sprinkle with chopped Oreos.
3. Slice, serve, and enjoy!