Was too lazy to make the caramel, just threw them in the pan.
Cake was amazing, plums were just a bit tangy, so crème fraiche is highly recommended (I had none on hand, so I just frothed like 30ml milk with powdered sugar and a tbsp of yoghurt; honestly, was as close as I could get, everyone liked it 👍 may be even better with honey instead of powdered sugar in this particular case)
All in all, easy to whip together if you skip the caramel (although easier for 2 to make, as 1 makes the caramel, while the other plums+cake).
Will definitely try the lime+plum combo next time: https://m.youtube.com/watch?v=bKgU30wub50