225g (8oz) Butter, softened
175g (6oz) Caster sugar
400g (14oz) Plain flour, plus extra for dusting
2 Eggs, separated
1tsp Baking powder
Pinch of salt
(1) Beat the softened butter in a large mixing bowl or in an electric food mixer to soften it a little more. Then with 150g (5oz) of the sugar gently beat until pale and fluffy. Beat the yolks lightly and slowly stir them into the mixture and then sift in the flour, baking powder and salt until it gives a smooth dough. Cover the dough in cling film and place in the fridge for 20 - 30 minutes.
(2) Preheat the oven to 180°C/ gas mark 4.
(3) Roll the dough out on a floured work surface to a thickness of about 6mm and use a
scone/ biscuit cutter (or a knife) to cut out biscuit shapes. Arrange on a couple of large baking sheets/ trays and place back in the fridge for 10 - 15 minutes before baking them in the oven for about 12 - 15 minutes or until just turning golden.
(4) Meanwhile, lightly beat the egg whites.
(5) Remove the biscuits from the oven. Working quickly, gently brush the egg whites on the biscuits. Sprinkle the biscuits with a little of the remaining sugar and replace them back in to the oven for 3 - 5 minutes or until golden, which gives them a crunchy top. Remove and leave to cool on the baking sheets/ trays for a few minutes before transferring them to a wire cooling rack to cool completely.