Preheat the oven to 350F (conventional). Lightly brush a 9" springform pan with butter on the bottom and sides. Wrap the outside of the pan tightly with 2-3 sheets of aluminum foil.

Grind Oreo cookies in a food processor until fine crumbs. Add melted butter and grind again. Transfer to the pan and press down firmly to create a tight crust.

Bake the crust for 8-10 minutes. Remove from the oven and reduce the temperature to 325F.

In a heat-proof bowl, mix semi-sweet chocolate, heavy cream, and coffee. Heat and stir over a double boiler until melted and smooth. Set aside to cool.

In a stand mixer, beat cream cheese until creamy and fluffy (3-4 minutes). Add sugar, cocoa powder, salt, and vanilla. Mix for 3-5 minutes, scraping the bowl.

Whisk eggs separately and add to the batter. Mix briefly. Add cooled ganache and sour cream; whip until combined.

Transfer batter to the pan with the crust. Tap the pan to remove air bubbles.

Create a water bath by placing the cheesecake pan in a larger pan with boiling water. Bake for 60-70 minutes.

Cool at room temperature for 2-3 hours, then refrigerate overnight (at least 8 hours).

Prepare ganache by boiling cream and pouring it over chocolate. Rest for 5 minutes, then mix until silky.

Whisk all ingredients until the cream reaches stiff peaks. Avoid overmixing.

Remove the cheesecake from the pan and transfer to a serving stand.

Pour slightly thickened ganache over the top and spread carefully.

Pipe rosettes around the edge with chocolate whipped cream.

Serve and savor the deliciousness!