Preheat oven to 350 F. Lightly grease a 9x13-inch baking dish with non-stick cooking spray.
If using fresh peaches, cut 6 peaches and place at the bottom of the pan. Since you won't have the syrup canned peaches come with, mix 1 cup of sugar with 1 cup of water and then pour over the fresh peaches.
DUMP the yellow cake mix over the peaches, pressing down firmly.
Cut thin slices from the 2 sticks of butter and place on top of the cake, making sure to cover every area.
Bake in the preheated oven for 60 minutes, or until the top is golden brown.
Enjoy - it's delicious on it's own or with a scoop of ice cream!