Peel clementines so that the white skin is completely removed. Divide clementines into columns. Beat the fat, sugar, salt and vanilla sugar with the whisk of the hand mixer until foamy.
Stir in the eggs bit by bit. Mix flour, starch and baking powder and stir in. Fold clementine slices into the dough. Pour the dough into a greased box form (25 cm long) sprinkled with semolina and bake in a preheated oven (electric range: 175 °C/ gas: level 2) for 55-60 minutes.
Take the cake out of the oven, prick it several times with a wooden stick and let it cool down a little. In the meantime, stir icing sugar and juice until smooth. Turn the cake out of the tin and brush it with the icing sugar.
Let the icing dry and serve decorated with lemon balm and clementine slices as desired. Makes about 20 pieces.