Wash plums and take the pits out.
Mix all ingredients together (except for the plums).
Add 3/4 of plums into the batter (leave some to put them on the top of the cake).
Put the batter into the baking tin. Decorate with left plums.
Bake in 180°C, 40-50 min.
After the cake has cooled sprinkle it with caster sugar. Enjoy!