Dark Chocolate Cheesecake

For the Base:

• Line the base and sides of 20cm loose-bottomed cake tin with greaseproof paper. Preheat the oven to 180°C.
• Blitz the biscuits in a food processor until you have fine crumbs. Add the melted butter and cocoa and mix again until completely combined.
• Press the base into the prepared tin and push down well with the bottom of a drinking glass. Bake for 10 minutes, then set aside to cool completely. Reduce the oven temperature to 140°C.

For the Cheesecake:

• To make the cheesecake, finely chop the chocolate and place in a heatproof bowl. Place over a pan of simmering water and stir until melted. Set aside to cool.
• Use a stand or electric mixer to beat the cream cheese and castor sugar together until smooth and creamy. Add the vanilla extract, sour cream and then the eggs, one at a time. Beat together until smooth. Stir in the flour.
• Gently fold in the melted chocolate and pour the mixture over the biscuit base. Bake the cheesecake for 1 hour or until it is set at the edges but the middle is slightly wobbly. Turn the oven off and open the door a crack, and leave the cheesecake in the oven to cool for 1 hour.
• Remove from the oven and allow the cheesecake to cool to room temperature. Refrigerate overnight.

For the Ganache:

• To make the ganache topping, finely chop the chocolate and place in a heatproof bowl with the butter and milk. Place over a pan of simmering water and stir gently until melted and smooth.
• Remove the cheesecake from tin and place onto a serving platter. Pour the ganache over the cold cheesecake, using a spatula to spread it evenly, allowing some to flow over the edges a little. Decorate with chocolate curls if desired.
• Before serving, let the cheesecake come to room temperature for at least 1 hour.