Preheat the oven to 375 degrees. Butter a shallow 2 quart baking dish.
In a bowl toss the berries with the remaining filling ingredients and spread evenly in the baking dish.
Make the topping: Cut butter into pieces. In a bowl with a pastry blender or in a food processor blend or pulse together flour, cornmeal, sugar, baking powder, salt, and butter until mixture resembles coarse meal. If using a food processor transfer mixture to a bowl. Add milk and vanilla and stir until mixture forms a dough.
Drop topping by rounded tablespoons onto berry filling (do not completely cover it) and bake in middle of oven 40 minutes, or until topping is golden and cooked through. Transfer cobbler to a rack to cool slightly.
Serve cobbler warm with ice cream.