Loved this quick to fix cake. Light and buttery, full of fresh berries, and with a delightful crunch from added sugar on top. Bakes in a cast iron skillet. Can use blueberries as well. From marthastewart.com. I used about 2 cups blackberries.
Preheat oven to 375 degrees. In a large bowl, whisk together flour, cornmeal, baking powder, salt, and 1 cup plus 2 tablespoons sugar. In another bowl, whisk together buttermilk, eggs, and 7 T melted butter; pour over flour mixture, stirring just to combine.
In a 10-inch cast iron skillet, heat remaining 1 tablespoon butter in the oven until melted and skillet is hot, about 5 minutes. Remove from oven; swirl to coat bottom of pan. Pour batter into skillet; scatter blackberries on top, and sprinkle with remaining 1/4 cup sugar.
Bake until top is evenly browned, 45 to 50 minutes. Let cool slightly, about 30 minutes. Serve warm or at room temperature.