Line the sides of 4 rings approximately 6cm/2½ inches in diameter, with greaseproof paper and place on a tray lined with greaseproof paper. Soak the gelatine in cold water.

Reserve a few blackcurrants for decoration. Place the remaining blackcurrants in a saucepan with 25g/1oz of the sugar and 50ml/2fl.oz water. Simmer gently until the sugar has melted and the blackcurrants are tender. Purée and pass through a fine sieve.

Put the biscuits and brown sugar in a bowl and mix well together. Pour on the melted butter and mix until all the crumbs are moistened. Divide the crumbs between the prepared rings and press down lightly. Chill until firm.

Mix the cream cheese and single cream together. Place the egg yolk and remaining sugar in a small bowl and whisk over a pan of hot water until thick, remove from the heat and whisk until cold.

Remove the gelatine from the water and squeeze out the excess moisture. Dissolve the gelatine in 15ml/1tbsp boiling water and stir into the egg mixture. Add the blackcurrant purée and the cheese mixture. Mix well and leave on one side stirring into the prepared rings. Place in the refrigerator.

Carefully remove the rings from the cheesecakes. Remove the greaseproof paper and decorate with the remaining cream whisked to piping consistency, and any reserved blackcurrants.