Summer-Fruit Cobbler

Ingredients

• 5 tablespoons unsalted butter, sliced, plus more for greasing pan
• 4 cups (6 to 8) sliced peeled nectarines
• 1 pint raspberries
• 2/3 cup granulated sugar, divided
• 2 tablespoons cornstarch
• 1 tablespoon fresh lemon juice
• 3/4 teaspoon salt, divided
• 1 1/4 cups all-purpose flour
• 1/2 cup fine cornmeal
• 2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 6 tablespoons lowfat buttermilk
• 1 tablespoon raw sugar