Finely chop dates. Bring 125 ml water to the boil. Mix dates and baking soda, pour boiling water over them and let them stand for about 15 minutes. Chop walnuts, except for 8 pieces for decoration. Mix flour, baking powder and chopped walnuts.
Whisk sugar, vanilla sugar, 1/2 teaspoon salt and 125 g margarine with the whisk of the hand mixer until white-creamy. Stir in the eggs one after the other. Stir in flour and date mixture. Pour into a greased springform pan (24 cm Ø) sprinkled with flour. Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 40 minutes. Remove the cake from the oven, let it cool down and take it out of the tin. For the icing, bring brown sugar, 2 tablespoons margarine and cream to the boil. Simmer for approx. 3 minutes until a homogenous mixture is formed. Spread the icing on the cake and decorate with the remaining walnuts.
Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 40 minutes. Remove the cake from the oven, let it cool down and take it out of the tin. For the icing, bring brown sugar, 2 tablespoons margarine and cream to the boil. Simmer for approx. 3 minutes until a homogenous mixture is formed. Spread the icing on the cake and decorate with the remaining walnuts. Cut the cake into pieces with a knife thinly coated with oil
Waiting time approx. 1 hour