Preheat the oven to 170˚C (150˚C fan oven, 325˚F, gas 3). Grease and line an 18cm (7inch) spring-form cake tin. Put the crushed biscuits in a bowl and mix in the Fine Dark Cocoa Powder and sugar. Bind together with the melted butter, mixing well until thoroughly blended.

Pile the mixture into the prepared tin, then carefully, using the back of a dessertspoon, press and mould the biscuit mixture over the bottom of the tin and up the sides of the tin to within 1cm (1/2inch) of the top. Smooth the crumb mixture with the back of the spoon to help make sure the inside of the tin is evenly coated in a crumb crust. Chill until required.

Now make the filling. Break the Extra Dark Chocolate into pieces and place in a heatproof bowl. Place over a saucepan of barely simmering water and leave to melt. Remove from the water, mix well and cool for 10 minutes.

Meanwhile, in a large bowl, mix the cream cheese, soured cream and Vanilla Paste together. Mix in the cooled chocolate – the mixture will thicken – and gradually beat in the eggs and sugar. Stir in all but 15g Chocolate Chunks.

Pile the chocolate cheese filling into the chilled crumb case and smooth the top. Sprinkle over the remaining Chocolate Chunks. Stand the tin on a baking tray and bake in the oven for about 1 hour until firm. Leave to cool in the tin for about 1 hour before removing. This cheesecake is delicious served warm or cooled completely and then chilled for at least 1 hour.