Bash the biscuits into fine crumbs in a bowl with the end of a rolling pin. Stir in the melted butter with a pinch of salt. Line a 20cm springform cake tin with baking paper and spoon in the biscuity crumbs. Press down into the base with the back of a spoon. Chill.

Melt the chocolate in short bursts in the microwave. Leave to cool.

Beat the soft cheese, mascarpone, icing sugar, cocoa and Baileys Chocolate Liqueur in a large bowl until just combined. Slowly stir in the cooled melted chocolate; if you do this too quickly the chocolate could seize up and you may get lumps of chocolate in the cheesecake. The soft cheese and mascarpone being at room temperature will also help with this.

Whip the cream to soft peaks in a separate bowl, then gently fold into the cheesecake mix, trying not to knock any air out of the mix. Spoon over the top of the chilled base and smooth over the top. Chill for 6 hours, or overnight, until set.

Run a knife under hot water, then use to loosen the sides of the cheesecake. Transfer to a plate and top with dark chocolate shavings or cocoa, then drizzle with a little more Baileys Chocolate to serve.