Lime & Blackcurrant Swirl Cheesecake

Serves 10

150g blackcurrants, fresh or frozen
275g caster sugar
175g biscuits
60g unsalted butter, melted
600g cream cheese, softened
175ml soured cream
2 eggs, plus 1 extra egg yolk
juice of 2 limes
zest of 1 lime

Preheat the oven to 150, gas mark 2.
Place the blackcurrants, 75g of the sugar and 1tbsp of water in a small saucepan.  Heat gently for 4-5 mins, stirring occasionally, until the fruit is soft but retains its shape, and is sitting in a pool of syrup.
Transfer 1/2 the blackcurrants to a sieve with most of the juice, and press through into a bowl, discarding the solids.  Set aside the pan of remaining blackcurrants and the bowl of puree and leave to cook until needed.
Process the biscuits in a food processor until crumbs or crush with a rolling pin.  Add the melted butter and mix until combined.
Press the crumb mixture into the base of a pie dish and store in the fridge until needed.
To make the filling, beat the cream cheese until smooth, then slowly add the soured cream, remaining sugar, eggs, lime juice and zest.  The mixture should now be smooth and thick.
Scatter the blackcurrants from the pan evenly over the crumb base and pour the cream cheese filling on top.  Add drops of the blackcurrant puree and swirl lightly with a knife to achieve a marbled effect.
Bake for 1 hour until firm to the touch.  Leave to cook at room temp and then store in the fridge.  Serve with any remaining blackcurrant puree.