SERVES 12

1. Grease the tin with oil and line the base and sides with parchment.

2. Melt the butter in a medium saucepan on the hob or in a bowl in the microwave. Blend the biscuits in a food processor, or seal in a food bag and bash with a rolling pin, to fine crumbs. Stir into the melted butter to coat evenly and press onto the tin base and about 4cm up the sides. Chill for 15 minutes to firm up.

3. Snap the chocolate into a small heatproof bowl and either melt in the microwave in 30-second blasts, stirring between each go, or over a pan of simmering water, shallow enough that the water doesn’t touch the bowl. Once melted, leave to cool to body temperature.

4. Briefly beat the cream cheese in a large bowl. Beat in the condensed milk and cooled chocolate until smooth. Spread evenly on the base. Cover with cling film and chill for at least 4 hours, until firm.

5. Reserve two-thirds of the blackberries (ideally the smallest ones) in a bowl. Pop the rest in a food processor, add the orange juice, icing sugar and crème de cassis (or cordial) and blitz until smooth. Pass through a fine sieve over the reserved berries. Cover and chill.

6. To make the ganache, snap the chocolate into a large heatproof bowl and melt either in the microwave in 30 second blasts, stirring between each go, or over a pan of simmering water, shallow enough that the water doesn’t touch the bowl. When melted, remove from the heat and set aside. Put the cream, milk and butter into a medium pan and bring to a simmer over a medium heat. Once simmering, remove and pour into the melted chocolate, stirring all the time until evenly blended to a smooth chocolate sauce. This can be made in advance and stored for 2-3 days in the fridge. (In which case, warm through gently in 30-second blasts in the microwave or over a pan of simmering water, until pourable). Leave aside to cool. About an hour before the cheesecake is ready, spread the ganache evenly over the top and return to the fridge to set.

7. To serve, carefully remove the cheesecake from the tin and peel off the paper. Sit on a cake stand, and spoon the reserved blackberries and berry sauce on top. Serve with crème fraîche.