Preheat the oven to 350°F (175°C). In a mixing bowl, combine sliced peaches, sugar, and lemon juice. Toss to coat the peaches evenly.

Spread the peach mixture evenly in the bottom of the baking dish.

Sprinkle the dry cake mix evenly over the peaches.

Drizzle the melted butter over the cake mix, ensuring even coverage. Sprinkle chopped pecans on top if using.

Bake in the preheated oven for 40-45 minutes or until the top is golden brown and the filling is bubbly.

Remove from the oven and let cool slightly before serving.