Wash and quarter each plum, discarding the stone inside. Peel the pears, cut into quarters lengthways, remove the stem and scoop out the middle core.
Add to a medium saucepan along with the plums, cinnamon, vanilla, syrup and 220ml of water. Place on a medium heat and simmer with the lid on for 20 minutes, stirring once or twice.
To serve, top with full-fat greek style yoghurt and lots of the warm juice from the pan. You can mash for baby or serve as is, as the fruit is really soft.
Leftovers will last a couple of days in the fridge, reheat in a saucepan or microwave if desired or eat cold.