This is an American classic.  A good blueberry muffin is hard to beat, and you can make loads in a single batch to hand around, or keep in an airtight container for a few days.

Method (makes 12)

• Cream together the butter and sugar until light and fluffy and then gradually add the eggs, beating between each addition until it is all incorporated.  
• Next sift the flour, baking powder and salt and fold a third of it into the butter mixture. 
• Add a third of the milk and then another third of the flour mixture.  
• Repeat until all ingredients have been used up, and then carefully fold in the blueberries.  
• Divide the mixture between 12 muffin cases and scatter the oats over them. 
• Bake in a preheated oven at 180ºC for 25 minutes.