• Preheat the oven for 15 minutes at 180°C.
• In a bowl, mix the butter with the sugar. When the mixture has whitened, add the egg and milk.
• Gradually add the yeast and flour.
• When the mixture is smooth, add the blueberries.
• Mix gently to spread the fruit around.
• Pour the mixture into muffin cups.
• Bake for 15 minutes.
• Leave to cool before eating.