Preheat the oven 350 F.
In a bowl of a standing mixer, combine milk, ⅓ cup of sugar, eggs, vanilla, salt and flour. Blend until the mixture is smooth and frothy.
Lightly grease 8*8 baking dish with butter and pour a ¼ inch layer of the batter. Place it in the oven and let the batter set for about 5 minutes until a film of batter forms on top of it.
Remove from the oven, spread blueberries and then the remaining sugar on top of the batter.
Pour on the remaining batter and smooth with the back of a wooden spoon.
Bake for 50 minutes.
Serve warm and enjoy!