Make a kneading dough from the first 4 ingredients and roll it out on a baking sheet (30 x 40 cm). Bake in a preheated oven at 200 ° C, hot air 180 ° C, gas 3-4 for about 12 minutes.
In the meantime, wash and stone the plums.
Make a batter from the remaining ingredients and spread on the baked and cooled shortcrust pastry base, place the plums in rows close together and bake the cake on the same oven settings for 35-40 minutes.
Sounds like a lot of work, but it`s not. It`s faster than a yeast cake and tastes 1000 times better. I am sure you will be delighted.