Step 1

Preheat the oven to 350 degrees F. Spray a 9-by-13-inch baking dish with cooking spray.

Step 2

Toss together the sliced peaches, brown sugar, granulated sugar, cornstarch, cinnamon, nutmeg, salt, and lemon juice in a large bowl. Let sit 15 minutes.

Step 3

Transfer to the prepared baking dish and top evenly with the cake mix. Cover the top with the slices of butter.

Step 4

Bake until golden brown and the juices are bubbling, 45 to 55 minutes. Let cool slightly before serving with ice cream.