Preheat the oven to 350 degrees F and spray a 9x13 baking dish with cooking spray.
Spread the frozen peaches out evenly, covering the bottom of the baking dish.
Sprinkle the entire bag of dry cake mix over the peaches.
Slowly, pour the 7UP or Sprite over the cake mix. Do not mix with a spoon. Just pour it on top to cover the cake mix well.
Cover the cobbler with foil and bake for 20 minutes.
Remove the foil and continue to bake for another 40 minutes.