Pre-heat the oven to 180°C (350°F) and prepare a muffin tray by greasing (or using muffin cases).
In a bowl, cream the butter and sugar, then beat in the eggs.
Sieve the flour, baking powder, salt, vanilla sugar/extract and cinnamon together, then add to the wet ingredients. Stir until just combined.
Add the milk and mix once more. Finally, stir in around half of the blueberries.
Spoon into muffin cases and top with the remaining blueberries.