10 oz plain flour
7 oz butter
5 oz castor sugar (plus extra for sprinkling)
2 oz currants
1 or 2 egg yolks
6 – 8 drops oil of Cassia
Mix all of the ingredients together adding a little milk if too dry. Roll out to about ⅜”/1 cm thick and cut with a fluted cutter.
Bake at 160˚C (conventional oven) for 10-15 minutes, until very lightly browned. Sprinkle with caster sugar as soon as you remove the biscuits from the oven, then cool on a rack.
The original recipe said 6 drops of oil of cassia, my mother-in-law has now increased this to 8, but do count the drops carefully as too strong a flavour of cassia ruins the biscuits.
Likewise, according to my husband, the biscuits are RUINED if they are cooked for too long. According to him, they should retain some substance in the middle and not be too biscuity. He does have some technical description of the degree of resistance to snapping the biscuits should have, but it is a bit too complicated to explain – let’s just say they shouldn’t snap too easily!
You can read more about the origins of this recipe here