In a 8x8-inch baking dish, mix blueberries with 1 C of sugar. Set aside. In a mixing bowl combine melted butter, 1 C sugar and vanilla. Add in flour, baking powder and salt. Stir in milk, until a smooth batter forms. Add more milk, if batter is too thick. Pour batter over berry mixture and smooth out as much as possible. Bake in a 350 degree oven, for 45 minutes to an hour, until a toothpick inserted into the center of the cake, comes out clean (make sure to insert the toothpick quite deep, to make sure the bottom of the cake is cooked through as well). If top begins to get too dark, cover with foil, for remainder of bake time. Serve warm, as is, or with fresh cream or vanilla ice cream.
