Pre heat the oven to 200c, place the muffin cups in the tray and set aside.
Whisk together butter, sugar, eggs and vanilla in a large bowl until light and fluffy. Easiest to do with an electric whisk, but can be done with a normal whisk too.
In a separate bowl combine flour, salt, baking powder.
Add the milk to the egg mixture and sieve in the bowl of flour in two batches to avoid forming lumps. If you accidentally manage to end up with a lumpy batter you can pass it all through the sieve and push any lumps through to break them up.
Fold in all but 25 grams of the blueberries (Set aside for the next step). Be gentle to not crush too many of the blueberries.
Transfer the batter into the muffin cups, don't fill more than 3/4 of the way up in the cups otherwise they might spill over. Finally add 2-3 blueberries on to the top each of the muffins pushing it down gently. This is done to make sure to have a nice and even spread of blueberries in the muffins.
Bake in the middle of the oven at 200C convection for around 20-25 minutes or until a skewer comes out clean when poked into the middle of the muffins.