Preheat oven to 375°F and grease an 8x8-inch baking dish or 6 individual ramekins.
In a medium bowl, combine blueberries, 2/3 cup sugar, cornstarch, lemon zest, and lemon juice. Toss gently and transfer to prepared baking dish.
In a large bowl, whisk together flour, 1/3 cup sugar, baking powder, and salt.
Add melted butter, milk, and vanilla extract to the dry ingredients and stir until just combined and smooth.
Pour batter evenly over the blueberries and spread gently to cover. Sprinkle raw sugar over the top.
Bake for 30-35 minutes until topping is golden and set, and blueberries are bubbling. Let cool for 10 minutes before serving warm.