Preheat oven to 375 degrees . Grease 8-inch square, parchment-lined baking dish. In large bowl, whisk together cornmeal, flour, 1/4 cup sugar, baking powder and salt. In another bowl, whisk together buttermilk, eggs and butter, then stir into flour mixture. Spread batter into prepared baking dish. Scatter 1 cup berries over top and press them into batter until mostly submerged; scatter remaining berries on top and sprinkle with remaining sugar. Bake until golden around the edges and springy to touch, 25 to 30 minutes. Let cool, 10 minutes. Serve warm or at room temperature.