Preheat the oven to 180℃ (160℃ fan)/350°F/gas mark 4.
Beat 75g (3oz) softened butter with 75g (3oz) caster sugar together until light and fluffy, then beat in 1 egg yolk.
Add a pinch of mixed spice, 50g (2oz) currants and 15g (½oz) mixed peel and mix to combine, then beat in 3tbsp milk.
Add 175g (6oz) plain flour and mix to a stiff dough. Roll out the dough to 6mm (¼in) thick then use a 7cm (3in) round cookie cutter cut out biscuits and transfer to a baking sheet. Gather up the trimmings, roll and repeat.
Lightly beat the egg white and brsuh the surface of the biscuits with the egg white, then sprinkle with a little granulated sugar.
Bake for 15 – 18 minutes until pale golden.
These bsicuits store well in an airtight conatiner for up to 2 weeks.