- STEP 1
Place the dates in a bowl with the butter and bicarbonate of soda. Pour over the boiling water and stir until the butter has melted. Set aside to cool.
- STEP 2
Preheat the oven to 180ºC (350ºF, gas mark 4). Lightly grease an 18 cm (7 in) round deep cake tin and line the bottom with baking parchment.
- STEP 3
Place the sugar and eggs in a large bowl and beat well to combine. Add the cooled date mixture, then sift in the flour, baking powder, mixed spice and salt. Add the walnuts and stir together until thoroughly mixed.
- STEP 4
Pour the mixture into the prepared tin and level the top. Bake for 1–1 1/4 hours or until the cake is risen and nicely browned and a skewer inserted in the centre comes out clean.
- STEP 5
Turn out onto a wire rack and leave to cool. The cake can be kept, wrapped in foil or stored in an airtight container, for up to 5 days.