Preheat the oven 350ºF. Grease an 8X8 baking dish with butter.
Place flour, ½cup sugar, salt and baking powder in a bowl and combine. Add the milk and butter, stir with a rubber spatula until just combined. Pour into baking dish and spread evenly.
Place blueberries evenly on top of batter. Sprinkle sugar over top and then drizzle vanilla on top of that.
Place in preheated oven for 35 to 45 minutes or until a toothpick comes out clean from the center. Allow to cool for 10 minutes before serving. Good on it's own, REALLY good with a scoop of vanilla ice cream.
Recipe by pretty plain janes at https://prettyplainjanes.com/2016/07/27/blueberry-crumble/