Preheat the oven to 180ºC/gas mark 4. Grease two or three baking sheets with a little butter.
In a bowl, mix together the butter, sugar, oats, flour, vanilla extract and eggs. Mix in the blueberries.
Drop 16 spoonfuls on to the prepared sheets and spread out with the edge of a spoon. Bake for 20-25 minutes until golden. Lift on to a wire rack and allow to cool.