For the Oreo Crust: Preheat the oven to 325°F. Line the bottom of your springform pan with parchment paper.
Pulse the Oreos in a food processor until they resemble sand. Drizzle in the melted butter and mix until the mixture holds together.
Press the mixture firmly into the bottom of a springform pan and 1-inch up the side. Place in the oven and bake for 10 minutes. Remove and set aside while you make the cheesecake filling.
For the Chocolate Cheesecake Filling: Add the semi-sweet chocolate to a microwave-safe bowl and heat in the microwave until melted and smooth. Set aside to cool.
In a mixer fitted with a paddle attachment, cream the softened cream cheese until completely smooth. Scrape down the sides and bottom of the bowl as needed to ensure no clumps remain. Mix in the granulated sugar, vanilla extract and cocoa powder. Mix just until fully combined
Add in the eggs one at a time, mixing fully and scraping the sides of the bowl before adding the next egg. Then pour in the melted and cooled semi-sweet chocolate. Mix until smooth and fully combined.
Pour the chocolate filling into the prepared crust. Bake for 20 to 25 minutes. Check the cheesecake at the 20-minute mark by gently tapping the side of the pan. If the center slightly jiggles, it is done.
Once done, turn off the oven and leave the oven door cracked open for 1 hour to cool slowly.
Remove from the oven and let it cool completely on the counter. Place in the refrigerator for at least 4 hours (preferably overnight) to fully set up.
For the Ganache: Warm the heavy cream in a small pan over medium heat just until hot to the touch, not simmering. Pour over the chocolate chips and let sit for 3 to 4 minutes before stirring until no clumps remain. Cool for 10 minutes.
Pour the cooled chocolate ganache over the top of the chilled cheesecake, smooth it out, let it set completely, then slice and serve! Enjoy!