Butter a 1 ½-quart baking dish, and then heat the oven to 350 F.
Arrange the berries in an even layer in the bottom of your baking dish.
Make the batter.
Pour the milk into a high-powered blender along with the sugar, vanilla, salt, eggs, and flour. Blend until they form a smooth batter.
Bake and Serve.
Pour the batter over the berries and then transfer to the oven and bake until set, and golden brown on top, about 45 minutes. Let the clafoutis cool in the pan for 5 to 10 minutes before serving.