Pre-heat oven to moderate (180 degrees celsius / 360 degrees fahrenheit, fan-forced) and lightly grease two baking trays.
Beat butter and add sugar gradually. Beat to a cream.
Add egg and beat again until smooth.
Sift together flour, baking powder, salt and spice. Gradually fold into mixture.
Add currants and peel and stir through until distributed throughout mixture.
Tip out mixture onto a floured bench and form into two rounds. Roll out the rounds to about 5-6mm thickness. Use round cutter to cut out biscuits and place on the trays. If the mixture becomes difficult to work with, place in the fridge for 15 minutes before proceeding.
Add enough lemon juice to the icing sugar to form a runny paste. Brush the tops of the biscuit with the lemon juice and icing sugar mixture.
Place trays into oven and bake for 15 minutes or until a golden colour.
Allow to cool for about 10 minutes on trays before using a spatula to transfer the biscuits to a cooling rack.
Notes
Storing:These biscuits can be stored in an airtight container at room temperature for up to one week.Freezing:They can also be stored in a freezer bag and frozen for up to a few months.Nutrition:The nutrition information is an automatically generated estimate and is not guaranteed to be accurate.