Put the first six ingredients in a bowl and stir well - but no more than 1 to 2 minutes. The short time is important so that the dough remains loose. Put the dough in a greased springform pan or a parchment-lined springform pan.
Wash, stone and halve the plums. Then spread on edge all around on the dough base.
Bake the cake in a preheated oven at 180 ° C top / bottom heat for approx. 45 - 60 minutes.