Pre-heat the oven to 180ۜ° or 170° fan forced .Grease and line an 8inch or 21cm cake pan
Pour the boiling water over the chopped dates and bi carb soda and leave to cool completely.
With an electric beater cream the butter and sugar until light in colour and creamy. Add the beaten egg and vanilla and mix for a couple of minutes until smooth.
Sift the flour with the baking soda and pinch of salt and gently fold into the creamed butter and sugar with a metal spoon.
Lastly add the dates and ½cup of chopped walnuts mixing until combined. Pour and spread evenly into the pan. Bake for approximately 45 minutes until golden brown and a skewer comes out clean when tested in the centre of the cake.
For The Icing
Boil together the sugar, cream and butter for 3 minutes. Allow to cool until only just warm but still runny. Spread over the cake and allow to drip over the sides. Sprinkle the entire cake with chopped walnuts.