250g packet plain chocolate biscuits
100g butter, melted
3 teaspoons gelatine powder
1kg cream cheese, at room temperature, chopped
140g (2/3 cup) caster sugar
3 teaspoons vanilla bean paste
125g dark chocolate, melted, cooled
1 1/2 teaspoons vegetable oil
125ml (1/2 cup) thickened cream
1/2 teaspoon cocoa powder, plus extra, to dust
Shaved chocolate, to decorate (optional)
- Grease a 18 x 28cm slice pan. Line the base and 2 long sides with baking paper, allowing the paper to overhang the long sides.
- Place the biscuits in a food processor and process until resembles fine crumbs. Add the butter and process until combined. Spoon into prepared pan. Use a flat-bottomed, straight-sided glass to press and evenly spread the mixture over the base. Place in the fridge for 30 minutes to chill.
- Place 60ml (1/4 cup) water in a small heatproof bowl. Sprinkle with the gelatine and stir until well combined. Place the bowl inside a larger heatproof bowl. Pour boiling water into the larger bowl until it reaches halfway up the side of the smaller bowl. Set aside, stirring occasionally, for 5 minutes or until the gelatine dissolves.
- Meanwhile, use electric beaters to beat the cream cheese in a large bowl until smooth. Add the sugar and vanilla. Beat until combined. Remove and reserve 2 cupfuls of the mixture. Add the gelatine to the remaining cream cheese mixture. Beat until combined.
- Combine the dark chocolate and oil in a bowl. Spread half the cream cheese mixture over the biscuit base. Drizzle over half the chocolate mixture to cover. Place dollops of the remaining cream cheese mixture over the chocolate layer and carefully spread to create another layer. Drizzle over the remaining chocolate mixture to cover.
- Use electric beaters to beat the cream and reserved cream cheese mixture in a bowl until the mixture thickens slightly. Spoon into a piping bag fitted with a ruffle nozzle (see note). Pipe the cream cheese mixture over the top of the slice. Dust with the cocoa. Place in the fridge for 4 hours or until the cheesecake is firm and set.
- Dust with extra cocoa and shaved chocolate, if using, just before serving.
A ruffle nozzle will give you the classic Viennetta look, but you can use a plain or star nozzle instead.