Preheat your oven to 350°F (175°C).
In a mixing bowl, combine blueberries, 1/2 cup sugar, and lemon juice.
Pour the blueberry mixture into a greased 9x9-inch baking dish.
In another bowl, whisk together flour, baking powder, salt, and remaining sugar.
Add milk, melted butter, and vanilla extract to the dry ingredients.
Stir until just combined; do not overmix.
Pour the batter over the blueberries, spreading it evenly.
Bake for 40-45 minutes, or until the top is golden brown.
Let it cool slightly before serving.
Serve warm, optionally with whipped cream or ice cream.