Warm up the milk, add the yeast, sugar and the melted butter. Mix it and let it rest for 5 minutes.
Mix flour and salt separately.
Add the milk mixture to it and mix until you have a smooth dough.
Cover it up and let it rise for 30-45 min.
Now add all the ingredients for the crumble topping together until you get the wanted texture. And place it in the fridge.
Use the time that is left to wash the plums and core them. I usually use as many plums as fit on the cake.
Preheat the oven to 175 degrees Celsius (Umluft).
Roll the dough out on a floured surface right in the baking tray or use a baking sheet.
Place the plums on top of it and cover them with the crumbles.
Now let it bake for around 40 minutes. Don't bake it too long because the dough will get dry then.