First knead the flour, icing sugar, 1 pinch of salt, butter in pieces and 1 egg with the dough hooks of the hand mixer, then quickly knead with your hands to a smooth short pastry. Form the dough into a ball, wrap in foil and chill for about 20 minutes.
Roll out the dough on the floured work surface until round (approx. 28 cm Ø). Grease a springform pan with (26 cm Ø) and sprinkle with flour. Put the dough into the form. Spread plum puree on top and chill again.
In the meantime, separate 3 eggs. Mix cream cheese, sour cream, egg yolk, 30 g starch and 100 g sugar. Beat the egg whites until stiff, while letting 50 g sugar trickle in. Beat 150 g cream until stiff. Fold the ice cream and cream into the cream one after the other.
Pour the cheese mixture onto the dough and smooth it down, bake in a preheated oven (electric cooker: 150 °C/ convection oven: 125 °C/ gas: see manufacturer) for 1 1/4-1 1/2 hours. Let the cake rest in the switched off oven with the oven door slightly open for 20-30 minutes, remove from the oven and let it cool down on a cake rack for 2-3 hours.
Meanwhile, for the compote, wash, halve and stone the plums and cut them into pieces. Put 20 g sugar and cinnamon stick into a pot and caramelise. Deglaze caramel with 200 ml nectar.
Add 1 sachet of vanillin sugar. Simmer for about 5 minutes until the caramel has dissolved. Stir the remaining nectar with 10 g starch until smooth, add and bring to the boil while stirring. Add the plums and simmer at low heat for about 1 minute.
Remove the cinnamon stick from the compote. Let the compote cool down. Spread on the cake. Whip 150 g of cream until stiff, add loosely. Drizzle with chocolate sauce.