I had this cobbler at my brother’s house. It was very good.
For the batter:
1 1/2 cups all purpose flour
2 teaspoons baking powder
1/2 teaspoon salt
1 cup milk
2 teaspoons vanilla
4 Tablespoons unsalted butter, softened
1 cup sugar
For the filling:
4 cups fresh blackberries
3/4 cup sugar
4 Tablespoons unsalted butter, cut into 1/2 inch pieces
1 cup boiling water
1. For the batter: Adjust an oven rack to the middle position and heat the oven to 350º. Grease a 13 by 9 inch baking pan. Whisk the flour, baking powder, and salt in a medium bowl. Whisk the milk and vanilla in a small bowl.
2. With an electric mixer at medium-high speed, beat the butter and sugar together until fluffy, about 2 minutes, scraping down the bowl as necessary. Reduce the speed to medium and add the flour mixture and milk mixture alternately in two batches, beating after each addition until combined. Spread the batter into the prepared pan.
3. For the filling: Scatter the blackberries evenly over the batter and sprinkle with the sugar. Dot the surface with the butter and slowly pour the water evenly over the top. Bake until the mixture is bubbling and the top is golden brown, about 45 minutes. Cool 10 minutes before serving.