Mix the cake mix as directed on box with eggs, oil and water.
In a bowl, melt the butter and then add the brown sugar and mix. Pour into a round cake pan.
Place the sliced peaches in the cake pan on top of the brown sugar and butter mixture. Pour the cake mixture slowly over the peaches.
Bake in the preheated oven until the top is golden brown and a toothpick inserted comes out clean, 20 to 30 minutes. Once removed from oven, let cool for 10 minutes, then place a plate over the cake and flip the pan.