For the base

• Prepare the biscuit crumbs: Place the chocolate biscuits in a food processor and pulse until they resemble fine sand. Alternatively, place them in a sealed zip-lock bag and crush with a rolling pin.
• Combine with butter: Transfer the biscuit crumbs to a medium bowl. Pour in the melted butter and mix thoroughly until all crumbs are moistened and the mixture holds together when pressed.
• Prepare the pan: Line the bottom of a 23-24 cm (9-10 inch) springform pan with parchment paper. For easy removal, you can also line the sides with acetate or parchment paper strips.
• Form the crust: Pour the biscuit mixture into the prepared pan. Press firmly and evenly into the bottom, using the flat bottom of a glass or measuring cup to create a smooth, compact layer.
• Chill: Refrigerate the crust for at least 30 minutes to firm up completely while you prepare the filling.

For the creamy filling

Bloom the gelatin:

• If using gelatin sheets: Soak them in a bowl of cold water for 10 minutes until softened.
• If using gelatin powder: Sprinkle the powder over 100ml cold water in a small bowl. Let it sit for 10 minutes to bloom.
• Prepare the cheese mixture: In a large bowl, combine the room-temperature mascarpone, Philadelphia cream cheese, powdered sugar, and vanilla seeds. Mix with a spatula or electric mixer on low speed until smooth, creamy, and lump-free. Set aside.
• Dissolve the gelatin: Gently warm the Baileys in a small saucepan over low heat or in the microwave for 30-40 seconds until warm but not boiling. Remove from heat.
• For sheet gelatin: Squeeze out excess water from the softened sheets and add them to the warm Baileys. Stir until completely dissolved.
• For powder gelatin: The gelatin will have formed a solid block. Add this to the warm Baileys and stir until completely dissolved.
• Cool the Baileys mixture: Set the Baileys-gelatin mixture aside to cool to room temperature (about 10-15 minutes). It should be warm to the touch but not hot, or it will melt the cheese mixture.
• Whip the cream: In a separate clean, chilled bowl, whip the heavy cream with an electric mixer until soft peaks form. The cream should hold its shape but still be soft and smooth—not stiff or grainy.

Combine the filling:

• Slowly pour the cooled Baileys-gelatin mixture into the cheese mixture while stirring continuously with a spatula until fully incorporated.
• Gently fold in the whipped cream in three additions, using a spatula and a cutting motion to maintain airiness. Mix until no white streaks remain and the filling is uniform.
• Assemble the cheesecake: Remove the crust from the refrigerator. Pour the creamy filling over the set base and spread evenly with a spatula. Gently tap the pan on the counter a few times to release any air bubbles.
• Chill to set: Cover the pan with plastic wrap or aluminum foil and refrigerate for at least 6 hours, preferably overnight, until the filling is completely firm and set.

For decoration

• Release the cheesecake: Once fully set, run a thin knife around the edge of the pan before releasing the springform clasp. Carefully remove the sides.
• Decorate: Garnish with chocolate decorations such as chocolate shavings, curls, or a light dusting of cocoa powder just before serving.
• Serve: For clean slices, use a sharp knife dipped in hot water and wiped dry between cuts.