FOR THE SHORTBREAD
125g soft unsalted butter
150g plain flour, sifted
1 tsp ground ginger
55g caster sugar, plus extra for sprinkling
Mix the butter with the flour, ginger and a pinch of salt, until it looks like breadcrumbs. Stir in the sugar and bring the dough together in a ball.
Roll the dough into a sausage shape about 6cm in diameter, and wrap in clingfilm. Chill for at least 30 minutes to rest the dough.
Preheat the oven to 180°C, fan 160°C, gas 4. Unwrap the dough and slice into 1cm-thick biscuits.
Arrange on a lined baking tray and bake for 16 minutes until pale gold and lightly crisp. Sprinkle with a little extra caster sugar, cool for 5 minutes on the tray, then transfer to a wire rack to cool completely.