Tip 150g of blueberries into a saucepan, then add 2 tbsp of sugar and 100ml of water and bring to the boil.
Lower the heat and wait until the berries start to burst and a purple juice forms.
Then set aside to cool.
Cut the flesh from 2 large mangoes, slicing it from the large, flat stones at their centres.
Discard the stones and skin.
Put the flesh into a blender together with the juice of half a lemon and process to a thick, smooth purée.
Stir in 200ml of thick Greek-style yoghurt, taking care not to overmix it – ideally you’ll have ribbons of yoghurt still visible throughout the fool as you scoop into it.
Pour the mixture into serving dishes, then swirl a little of the blueberry purée through each one with a spoon.
Top with a few fresh berries, if you like.
