Prepare the Oven: Preheat the oven to 350°F (175°C). Lightly grease a 9×13-inch baking dish to ensure the cake doesn't stick and can be easily served after baking.

Prepare the Peach Filling: Pour the two undrained cans of peaches and one drained can into the baking dish. Add the vanilla extract, cinnamon, and nutmeg if using. Gently stir until evenly combined, then spread the peaches into an even layer. This will create a flavorful base for the cake topping.

Add the Cake Mix: Sprinkle the dry cake mix evenly over the peaches. Do not stir. Use a spatula to spread the mix into an even layer if needed. This layering is crucial for achieving the distinct textures of the fruit and cake topping.

Add the Butter: Slowly drizzle the melted butter over the entire surface of the cake mix. Cover as much of the dry mix as possible to encourage even browning. If using, sprinkle the chopped pecans evenly over the top. This step is essential for creating a rich, buttery crust.

Bake: Bake for 45 to 50 minutes, until the topping is deep golden brown and the peach filling is bubbling around the edges. If small dry patches remain after 30 minutes, drizzle 1 to 2 tablespoons of additional melted butter over those areas to ensure a moist topping.

Cool: Transfer the baking dish to a cooling rack. Allow the cake to cool for 10 minutes before serving so the filling can thicken slightly. This cooling period helps the flavors meld and makes serving easier.

Serve: Serve warm with vanilla ice cream, whipped cream, or fresh peach slices if desired. The warm dessert pairs beautifully with cold toppings, enhancing the overall experience.