Grease a box form (approx. 25 cm long; min. 1.5 l capacity) and dust with flour. Cream fat, 200 g sugar, vanilla sugar, lemon peel and 1 pinch of salt. Stir in the eggs one by one. Mix flour, starch and baking powder and stir in portions briefly.
Spread the dough into the mould. Bake in the preheated oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2) for approx. 50 minutes. Cool in the tin for about 15 minutes.
Remove the cake from the mould, prick several times with 1 wooden skewer and sprinkle with lemon juice, up to 3 tablespoons. Cool down on a cake rack.
Cut the nuts into thin leaves. Roast without fat, cool down. For the icing, mix icing sugar and 3 tablespoons lemon juice. Spread on the cake. Sprinkle nut flakes on top. Let the icing dry.