1. Put the prunes and dried fruit in a small saucepan and cover with the cold tea. Stir in all the spices and orange zest. Simmer together for 5 minutes then leave to cool.
2. Drain the fruit and put the prunes and roughly half the dried fruit into a blender or food processor with the custard and blitz till smooth.
3. Transfer to a mixing bowl and fold in the remaining dried fruit and the yoghurt.
4. In a separate bowl, whisk the egg whites into soft peaks and fold into the yoghurt mixture using a large metal spoon.
5. Transfer to a shallow, plastic freezer box and freeze for an hour.
6. Stir gently, mixing the frozen sides of the mixture into the middle and return to the freezer for a further hour, then repeat. The stirring helps the texture of the ice cream. Repeat the stirring until the ice cream is firm.
- There's no need for an ice cream machine but if you do have one, add the reserved dried fruits after about 15 minutes of churning.
- The longer the ice cream is kept frozen the firmer it will become so it's best eaten within 24 hours of making. If you want to get ahead, make the basic mixture to the end of step 3 and keep chilled. Finish with the egg whites and freeze as above when needed.
- Delicious served with a compote of sliced pear, clementines and sweet black grapes