Preheat your oven to 325°F (165°C) and grease a 9-inch springform pan, lining it with parchment paper for easy removal.

In a medium saucepan, combine frozen raspberries, water, sugar, and cornstarch. Cook over medium heat, stirring often, until the mixture thickens and starts to bubble, about 20-25 minutes. Remove from heat and let it cool slightly.

In a bowl, mix the crushed Oreo cookies with the melted butter until fully combined. Press this mixture firmly into the bottom of the prepared springform pan, creating an even layer.

In a microwave-safe bowl, combine the chocolate chips with 1/4 cup of heavy cream. Microwave in 30-second intervals, stirring in between, until the chocolate is melted and smooth.

In your stand mixer, begin mixing the cream cheese on low speed until smooth and creamy. Gradually add in the granulated sugar and the cocoa powder, mixing well.

Now, add the eggs one by one, making sure to scrape down the sides of the bowl after each addition. Once combined, add the remaining heavy cream and vanilla extract.

Finally, gently fold in the melted chocolate until fully incorporated.

Pour half of the cheesecake filling into the crust. Spoon in some of the raspberry sauce and swirl gently with a knife. Add the remaining cheesecake filling on top, followed by dollops of the raspberry sauce, and swirl again.

Place the springform pan in a larger pan and fill it with hot water halfway up the sides. This creates a steamy environment that helps in even baking and prevents cracks.

Place in the preheated oven and bake for 100-105 minutes. The cheesecake should be set around the edges but slightly jiggly in the center.

Once done, turn off the oven and let the cheesecake cool in the oven with the door slightly ajar for about an hour.

Afterward, transfer it to the fridge and chill for at least 4 hours, preferably overnight.

Before serving, garnish with fresh mint leaves and drizzle with any remaining raspberry sauce.