Preheat the oven to 170°C. Line a 9 inch cake with oil and then baking paper.
In a heat proof bowl add the warm water, chopped dates, baking soda and orange juice. Set aside.
In a mixing bowl add the eggs and the sugar, whisk well until the sugar is dissolved and the mixture has gotten pale.
Add the butter and vanilla, whisk briefly.
Sift over the flour and spices, add the salt and chopped walnuts. Pour the date mixture with all the liquid into the bowl and using the spatula fold the ingredients together until combined.
Transfer to the baking tin and top with additional walnuts and granulated sugar.
Bake for 35 – 38 mins until a toothpick inserted comes out clean.