Blueberries are one of the many fruits that combine deliciously with the richness of chocolate in cakes, while still retaining their own distinctive flavour.
Preheat the oven to 190°C/375°F/Gas 5. Arrange 12 paper cases in a muffin tin (pan). Melt the butter and chocolate in a pan over a medium heat, stirring frequently, until smooth. Remove from the heat and allow to cool slightly.