- Pre-heat the oven to 200°C/400°F/Gas Mark 6.
- Lightly grease 3 baking trays.
- Measure the butter and sugar into a bowl and mix together until light and fluffy.
- Beat in the separated egg yolk.
- Sift in the flour and lemon rind and mix well.
- Add the currants and enough milk to give a fairly soft dough.
- Knead the mixture on to a lightly floured surface and roll out to a thickness of 1/4 inch.
- Cut into rounds using a 2.5 inch fluted cutter, there should be roughly 24 biscuits.
- Place these rounds onto the prepared baking trays and bake in the pre-heated oven for about 10 minutes.
- Remove from the oven, brush the biscuits with a lightly beaten egg white, sprinkle with a little caster sugar and return to the oven for another 4-5 minutes or until lightly golden brown.
- Lift the biscuits out on to a wire rack to cool.
- Store in an airtight container.
200g (7oz) Mortons Plain Flour
100g (4oz) softened butter
75g (3oz) caster sugar
1 egg separated
Grated rind of 1 lemon
50g (2oz) currants
1-2 tbsp of milk