Crush 300 g of digestive biscuits into fine crumbs and mix them with 135 g of melted unsalted butter and 1 tablespoon of cocoa powder in a bowl. Press the mixture into a 23 cm springform tin and chill for 30 minutes.

In a large mixing bowl, whisk together 750 g of room temperature full-fat cream cheese, 175 g of icing sugar, and 40 g of cocoa powder until smooth. Gradually add 300 ml of double cream and whisk until the mixture thickens, about 3-4 minutes.

Spoon the cream cheese filling over the biscuit layer in the springform tin. Smooth the top and chill for at least 4 hours or overnight.

Combine 65 g of dark chocolate and 65 ml of double cream in a microwave-safe bowl. Heat in 15-second intervals until smooth. Pour the ganache over the chilled cheesecake.

Melt 30 g of white chocolate with 15 ml of double cream for the spiderweb design. Optionally mix in Sugarflair superwhite powder.

Pipe a spiral of white chocolate ganache onto the cheesecake surface. Use a cocktail stick to draw lines from the center to the edges to create a spiderweb effect.

Refrigerate the cheesecake for an additional 1-2 hours to set the ganache. Remove the springform tin and slice to serve.