Preheat your oven to 350°F (175°C).

In a food processor, blend 24 Oreo cookies until fine crumbs. Melt 5 tablespoons of unsalted butter and mix with the crumbs. Press this mixture into the bottom of a 9-inch springform pan. Bake for 10 minutes and let cool.

In a mixing bowl, beat 16 ounces of cream cheese and 1 cup of granulated sugar until smooth. Add 3 large eggs, one at a time, mixing well. Add the red velvet cake mix and 1 teaspoon of vanilla extract; blend until smooth.

In another bowl, beat another 16 ounces of cream cheese with 1 cup of sugar and add 3 more eggs and 1 teaspoon of vanilla extract. Mix until smooth.

Pour the red velvet mixture over the cooled Oreo crust. Spoon and spread the vanilla cheesecake layer on top. Bake for 45-50 minutes until the edges are set and center jiggles slightly.

Turn off the oven and crack the door open. Let the cheesecake cool in the oven for 1 hour. Then cool to room temperature and refrigerate for a minimum of 6 hours or overnight.

For the ganache, heat 1 cup of heavy cream until simmering. Pour over 8 ounces of chopped dark chocolate in a bowl. Stir until smooth. Let cool slightly before pouring over the cheesecake.

Carefully remove the cheesecake from the springform pan and serve topped with whipped cream or crushed Oreo cookies.