Preheat the oven to 375 F/ 190 C/ gas mark 5. Place the plum halves in your dish, add the powdered sugar and 1 tablespoon of flour and stir well to combine.
In a large bowl combine the topping ingredients and using a knife cut the coconut oil into the flour mixture. Rub the mixture using your fingertips and between palms of your hands until it becomes crumbly, dotted with large clumps. Scatter the mixture over the plums without pressing it down.
Bake for 30 minutes. Remove from the oven and leave to cool a little before serving.
This easy plum crisp is highly adaptable and you can experiment with the ingredients to suit your preference. For example you could use only one type of seeds or add some crushed nuts into the topping mixture.
I used wholewheat flour but you could swap that for plain flour if you prefer.
You could also add a bit of nutmeg or use mixed spice, instead of just the cinnamon and ginger.
Serve with a dollop of yogurt or simply on its own. It's best eaten hot or at least warm.