Preheat your oven to 350°F (175°C).
In a bowl, mix the berries, sugar, cornstarch, and vanilla extract.
Pour the berry mixture into a greased baking dish.
In another bowl, combine flour, baking powder, and salt.
Stir in melted butter and milk until just combined.
Drop spoonfuls of the batter over the berry mixture.
Bake in the preheated oven for 30-35 minutes, or until the topping is golden brown.
Check for doneness with a toothpick; it should come out clean.
Let cool for a few minutes before serving.
Serve warm with ice cream or whipped cream.