12cupsapplespeeled, cored and diced (about 4 pounds)
For the topping
Prep: Heat oven to 375°F. Spray a 9×13 pan with nonstick cooking spray.
Assemble filling: Place diced apples in prepared pan. Combine brown sugar, cornstarch and cinnamon in a small bowl. Stir into apples in pan, then stir in apple juice. Set aside.
Assemble topping: Combine flour, granulated sugar, cinnamon, baking powder and salt in a large mixing bowl. Cut in butter until coarse crumbs form. Pour in buttermilk and stir JUST until combined.
Assemble cobbler: Spoon batter over apple filling, then bake in the hot oven for 40 - 45 minutes, or until filling is bubbly and topping is puffed up and golden brown. Rest at room temperature for 15-20 minutes before serving.