Wash and stone the plums. Mix all dry ingredients in a bowl. Then add 450 ml of almond milk (possibly 1 - 2 tablespoons more) while stirring with a whisk and stir the liquid dough so that no lumps are formed.
Put the dough in a springform pan (26 cm) lined with baking paper and place the plums on top. Bake in the preheated oven for approx. 45 - 55 minutes at 180 degrees. The time varies depending on the furnace!
Make a stick test - the cake is ready when it is lightly browned. Let cool and then dust with powdered sugar.