Grease a fat pan (approx. 32 x 39 cm; at least 3.5 cm deep). Wash, halve and stone the plums. Bring 100 g butter, cream, brown sugar and 1 packet of vanilla sugar to the boil in a small pan and simmer for about 5 minutes.
Carefully stir in the flaked almonds, then simmer for 2-3 minutes. Remove from the heat and let it cool down for about 10 minutes, stirring carefully several times.
Cream 250 g butter, sugar, 1 packet of vanilla sugar and 1 pinch of salt with the whisk of the hand mixer. Stir in the eggs one by one. Mix flour, starch and baking powder and stir into the batter in portions.
Spread the dough on the fat pan. Spread plums loosely on top. Spread almond icing with a tablespoon as a blob on the cake. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for about 30 minutes.
Let it cool down.