A light coffee-flavoured sponge with crunchy walnuts, topped with a delicious creamy frosting. It is perfect with a cup of freshly brewed coffee or tea.
Preheat the oven to moderate 180°C (350°F/Gas 4). Line a 20 cm (8 inch) diameter, 6.5 cm (2½ inch) deep cake tin (see Chef’s techniques). Grease the paper and dust with flour. Set on a baking tray.