Start by preheating your oven to 350 degrees.
Then, grease a 9x13 pan with some cooking spray or butter.
To start making the cake, simply pour the 2 cans of peaches (and their juices) into prepared baking dish.
Then, evenly sprinkle the cinnamon and brown sugar on top.
Sprinkle The dry cake mix on top of the fruit mixture, making sure it's a complete layer that covers all fruit. Do not stir!
Arrange thin slices of butter evenly over the cake mix, trying to cover as much as possible with the butter.
Sprinkle the chopped pecans over the butter, if using. Bake in the preheated oven for 45-50 minutes. Or until the top is golden brown and edges are bubbling.
Allow to cool for 15 minutes before serving. Top with some vanilla ice cream or whipped cream if desired.