1.Combine sifted flour, caster sugar, nuts and hard boiled egg yolk in medium bowl, rub in butter. Stir in egg yolk until ingredients come together.
2.Turn dough onto floured surface, knead gently until smooth. Cut dough in half, roll each portion between sheets of baking paper to 3mm (⅛-inch) thickness. Refrigerate 30 minutes.
3.Preheat oven to 140°C (120°C fan forced). Grease oven trays, line with baking paper. Cut 24 x 5cm (2-inch) fluted rounds from each portion of dough, place about 2.5cm (1 inch) apart on trays.
4.Cut 2.5cm (1-inch) fluted rounds from centre of half the rounds.
5.Bake biscuits about 15 minutes. Cool on trays.
6.Sandwich biscuits with jam. Serve dusted with sifted icing sugar.
You can substitute the fig and ginger jam for any jam of your choice. These biscuits are best served on the day they are made. Store unfilled biscuits in an airtight container for up to 1 week.Note