Preheat oven to 350ºF.
Mix the butter and sugar until it's fluffy.
Slowly add the eggs then the vanilla.
In a separate bowl mix the flour, salt, and baking powder.
Alternately add the dry mix and the milk to the wet mix.
Mix in the blueberries.
Place into the muffin tin. (should be enough for 12 huge muffins or 24 regular size muffins) and sprinkle extra sugar over the top of each muffin.
Bake for about 35 minutes. (Keep an eye on them. Boat ovens are funny so my timing might be off. If you see them baking golden and the toothpick goes in and comes out clean they are done.)