Preheat oven to 350 degrees. Line the bottom of an 8-9″ springform pan with parchment paper. Place peaches slices decoratively in pan. Set aside.
Melt butter on stovetop and mix in brown sugar. Simmer until slightly thick. Pour over peaches. Add cinnamon and nutmeg to taste.
Prepare cake mix per box instructions. Pour over peach mixture. Smooth out.
Bake for 35 min or until an inserted knife comes out clean.
Serve with whipped topping.