Stir margarine until creamy. Stir in 250 g sugar and 3 eggs bit by bit for about 3 minutes.
Mix flour, cocoa and baking soda and stir into the fat-egg-sugar mixture alternately with the cream.
Spread the dough on a greased baking tray (approx. 35 x 40 cm) sprinkled with breadcrumbs. Bake in the preheated oven (electric cooker: 200 °C / convection oven: 175 °C/ gas: level 3) for 15-20 minutes. Let them cool down.
For the buttercream, stir 2 tablespoons of milk, 2 tablespoons of sugar and pudding powder until smooth. Boil up the remaining milk. Stir in the pudding powder and bring to the boil. Let it cool down, stirring several times to prevent skin formation.
Mix 250 g butter and icing sugar. Stir in lukewarm pudding until smooth by the spoonful. Spread on the cooled down cake base.
Melt 100 g butter. Roast the coconut flakes and 100 g sugar in it while stirring until golden brown. Remove from the heat and let it cool down. Mix in 1 egg well and spread the "sawdust" on the cream.