Line a 20cm/8” round deep, loose bottom cake tin with parchment paper and pre-heat the oven.
Put the dates and water into a saucepan and bring slowly to the boil. Remove from the heat, stir in the bicarbonate of soda and leave to cool.
Break the eggs into a mixing bowl, add the sugar and beat together until light and airy.
Mix in the oil followed by the self-raising flour.
Stir in the date mixture and walnuts. Tip the mixture into your prepared cake tin and smooth the top. Bake for 55-60 minutes.
Allow to cool in the tin for 20 minutes before turning out onto a wire rack. Sieve a little icing sugar over the cold cake before serving.