Place the chocolate cookies into a food processor and pulse until a fine consistency. Drizzle in the melted butter and process until the crumbs start to clump together.

Cover an 8 - inch springform cake pan with parchment paper. Press down the crumbs into the pan, and place in the fridge for 10 minutes.

Meanwhile, beat the cream cheese, mascarpone, powdered sugar, and vanilla together in a large bowl, until light and fluffy.

Beat the cold heavy cream until soft peaks appear. Fold the whipped cream into the mascarpone mixture until just combined.

Mix the gelatin and water. Let stand for 5 minutes. Microwave the gelatine until it dissolves, but do not boil. Set aside to cool.

Add the cooled, dissolved gelatin to the bowl of tiramisu filling. Mix until just combined. Do not overmix.

Remove the cookie base from the fridge. Spread ⅓ of the tiramisu filling over the crumbs.

In a small bowl, add the coffee-flavored liqueur or the rum to your strong coffee. Dip the ladyfingers into the coffee mixture, one at a time. Then add to the springform pan. Break the cookies to fit, as needed.

Spread another ⅓ of the filling mixture over the ladyfingers. 

Transfer the remaining tiramisu filling into a piping bag, and pipe on top of the cake to make a decorative topping as desired.

Set the cheesecake in the fridge to chill for at least 3 hours, or overnight.

To serve, carefully remove the cheesecake from the pan. Dust the top of the cheesecake with cocoa powder, slice, and serve!