1.Beat butter, brown sugar and egg in small bowl with electric mixer until smooth.
2.Stir in combined cooled coffee and water, then sifted flours in 2 batches. Mix to a soft dough, knead gently on lightly floured surface until smooth.
3.Roll dough between sheets of baking paper until 5mm thick. Cut into 5cm rounds, place about 4cm apart on greased oven trays, top with nuts.
4.Bake in moderate oven about 12 minutes or until lightly browned. Cool on wire racks.
5.Dust biscuits with combined sifted icing sugar and extra coffee. Dip half of each biscuit into combined chocolate and oil. Leave to set on wire racks.