Whisk butter, 140 g sugar and 1 packet of vanilla sugar until creamy with the whisk of the hand mixer. Add quark, cream and eggs and stir well. Stir milk and 75 g starch until smooth, add to the quark mixture and stir in.
Wrap a springform pan (Ø 26 cm) tightly with foil from the outside. Grease the mould. Pour in cheese mixture. Slide a fat pan onto the middle rail of the oven and fill half of it with hot water.
Place the springform pan in a hot water bath and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 1 hour. Turn off the oven and open the oven door a little bit.
Let the cake cool down for at least 2 hours. Take out and let cool on a cake rack.
In the meantime, wash, halve and stone the plums for the compote. Put 2 tablespoons of sugar and cinnamon stick into a pot and caramelise. Deglaze caramel with 200 ml nectar. Add 1 packet of vanilla 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, fill the compote into a bowl and let it cool down.
Bring 50 ml water with 50 g sugar to the boil in a small pan and reduce to a light caramel. Add sesame seeds and caramelise briefly until the caramel has a golden brown colour. Pour immediately onto a piece of baking paper and spread.
Allow to cool and break into pieces. Remove the cake from the tin and arrange on a plate. Put some plum compote in the middle of the cake. Decorate with sesame caramel and dust with icing sugar.
Add the rest of the compote.