Preheat your oven to 350°F (175°C). Line a 9-inch springform pan and an 8-inch round pan with parchment paper and spray insides with non-stick spray.

In a medium mixing bowl, whisk together the flour, cocoa powder, and salt until combined. Set aside.

In a large mixing bowl, cream butter and sugar until light and fluffy. Add in sour cream, vegetable oil, vanilla extract, eggs, and red food coloring, mixing until smooth.

Gradually incorporate the dry mixture with the buttermilk, mixing until just combined. Fold in baking soda and vinegar.

Divide the batter between the pans and bake for 18-20 minutes or until the cakes spring back when pressed. Cool on wire racks.

Crush Oreos and beat cream cheese until smooth. Mix in crushed Oreos, sugar, cornstarch, sour cream, vanilla extract, and eggs until creamy.

Fold in remaining Oreo crumbs into the filling. Pour cheesecake mixture over the cool red velvet base and layer with the second cake.

Place in a water bath and bake at 300°F (150°C) for 90 minutes. Let cool gradually in the oven, then refrigerate overnight.

Prepare the ganache by heating heavy cream, then pour over dark chocolate chips. Stir until smooth.

Pour ganache over cheesecake, allowing it to drip down the sides. Top with crumbled red velvet and cream cheese frosting if desired.