Preheat oven to 350°. Spray 6 (2-cup) baking dishes with cooking spray.
In a large bowl, whisk together ⅓ cup granulated sugar and cornstarch. Stir in nectarines, raspberries, and lemon juice until well coated. Divide mixture among prepared baking dishes.
In a medium bowl, whisk together flour, salt, baking powder, and remaining ¼ cup granulated sugar. Using a pastry blender, cut in butter until mixture is crumbly. Stir in buttermilk until combined. Drop dough by spoonfuls onto fruit mixture; sprinkle with turbinado sugar.
Bake until top is golden brown and filling is bubbly, 45 to 50 minutes. Let cool for 20 to 30 minutes; serve with ice cream.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/nectarine-raspberry-cobblers-recipe/