1. Preheat the oven to 170C/325F/gas mark
2. Grease a 22cm (9") springform or loose-based cake tin.
3. Melt the butter and mix in the crushed biscuits, then press the mixture into the base of the cake tin. Put it to one side for a moment.
4. Beat the soft cheese, egg yolks, sugar and vanilla essence until well blended, then fold in the flour and Yogurt.
5.Fold in the handful of sliced blackcurrants into the mixture.
6. Whisk the egg whites until they're stiff and fold into the mixture.
7.Pour it all into the tin, level the top and bake in the oven for 1 hour to 80 minutes until the cheesecake feels firm.
8.Turn off the heat and let the cheesecake cool in the oven with the door open for 1 hour.
5. Slice it up and enjoy!
Decorate with blackcurrants. Glaze them for that extra zing !