Preheat your oven to 350°F (175°C).
Grease a 9x13 inch baking dish.
Spread the sliced apples evenly in the bottom of the dish.
Mix the sugar and cinnamon, then sprinkle it over the apples.
Distribute the dry cake mix over the apple mixture.
Pour the melted butter over the top of the cake mix.
Sprinkle chopped nuts on top if desired.
Bake for 45 minutes or until golden brown.
Let it cool for a few minutes before serving.
Serve warm with ice cream or whipped cream.