Heat the oven to 350°F (175°C), then lightly grease a 9-by-13-inch baking dish. Pour both cans of peaches and all of their heavy syrup into the dish, spreading the peaches evenly.

Sprinkle the dry yellow cake mix evenly over the peaches. Do not stir the cake mix into the fruit, because the separate layers create the signature cobbler-like topping.

Drizzle the melted butter across the entire surface, or arrange very thin butter slices so they cover as much of the cake mix as possible. Pay special attention to the corners and edges, where dry cake mix can otherwise remain powdery.

Bake for 45–50 minutes, until the top is golden brown and the peach mixture is bubbling around the edges. If the top browns quickly, continue checking the fruit bubbles and avoid stirring the layers.

Let the dessert stand for 10–15 minutes before serving. Spoon it into bowls while warm and add vanilla ice cream or whipped cream if desired.