1. Line an 8×8-inch (20 cm) square baking pan with parchment paper, leaving overhang for easy removal.

2. In a bowl, mix the chocolate biscuit crumbs, melted butter, and cocoa powder until evenly moistened.

3. Press the mixture firmly into the bottom of the prepared pan and refrigerate for 20 minutes.

4. In a large bowl, beat the softened cream cheese, powdered sugar, and vanilla extract until smooth and creamy.

5. In a separate bowl, whip the heavy cream to stiff peaks.

6. Gently fold the whipped cream into the cream cheese mixture until fully combined.

7. Spread the cheesecake filling evenly over the chilled crust and smooth the top.

8. To make the ganache, heat the heavy cream until steaming but not boiling.

9. Pour the hot cream over the chopped dark chocolate and let sit for 2 minutes.

10. Stir until smooth and glossy.

11. Pour the ganache over the cheesecake layer and spread evenly.

12. Refrigerate for at least 4 hours, preferably overnight, until fully set.

13. Lift the bars from the pan using the parchment overhang, slice into squares, and serve chilled.