Preheat the oven to 180°C. Grease the sides of a baking tin with a little of the coconut oil.
Melt the rest of the coconut oil in a small pan over a medium heat, then leave to cool slightly. Meanwhile, sieve the flour and baking powder into a large bowl, set aside. Beat the sugar and melted coconut oil, then add eggs and flour, mix well.
Pour the batter into the baking tin and push the plums into the mixture. Bake for 40 minutes. Leave to cool on a wire rack, then serve.
GF – make sure the ingredient doesn’t contain traces of gluten!