Preheat the oven to 350 degrees and lightly butter a 13×9 inch baking pan
Pour two cans of peaches and the peach juice into the bottom of the pan, drain the third can and pour the canned peaches in the pan.
Pour in the vanilla extract and gently stir.
In a small bowl combine the brown sugar, corn starch and cinnamon, mix well.
Sprinkle the brown sugar mixture across the top of the peaches.
Sprinkle the dry cake mix over the peaches as evenly as possible gently smoothing with a spatula if necessary.
Pour the melted butter over the cake mix evenly, it is ok if there are dry patches of cake mix.
Place in the oven and bake for 45-50 minutes or until the top of the cobbler is golden brown and the peaches are bubbling around the sides.
Allow to cool before serving.