
This indulgent no-bake dessert features layers of crunchy chocolate sandwich cookies and a velvety mascarpone cream. It is an effortless showstopper that transforms into a soft, cake-like texture after chilling overnight.
Prepare the cake tin by lightly greasing a 20cm springform or loose-bottomed tin with a little flavourless oil. Line the base and sides completely with baking parchment to ensure the cake can be removed easily later.
In a large mixing bowl, combine the double cream, mascarpone, vanilla extract, and icing sugar. Whisk the mixture until it is smooth and just begins to hold soft peaks. Be careful not to over-whisk, as the mascarpone can thicken quickly.
Create the base layer by arranging a single layer of cookies at the bottom of the tin. Don't worry about small gaps, as the cream will fill them. Spoon about one-third of the cream mixture over the cookies and use a spatula to smooth it out to the edges.
Repeat the layering process twice more with the remaining cookies and cream, finishing with a smooth layer of cream on top. Cover the tin tightly with plastic wrap and refrigerate for at least 24 hours, or up to 48 hours, to allow the cookies to soften.
When ready to serve, melt the dark chocolate in the microwave in 20-second bursts, or in a heatproof bowl over a pan of simmering water. Let the chocolate cool for about 10 minutes.
Carefully remove the cake from the tin and peel away the parchment paper. Drizzle the melted chocolate over the top, allowing it to drip down the sides. Finish by crumbling extra cookies over the top. Serve immediately or chill for another hour to set the chocolate.
For the best results, ensure the cake chills for the full 24 hours; this is what gives the cookies their signature cake-like texture. If you prefer a lighter version, you can substitute the mascarpone with a standard full-fat soft cheese.