Preheat oven to 350 degrees. With the 1 tablespoon butter, grease the bottom and sides of a 9 x 13 baking dish. Evenly spread the 2 tablespoons brown sugar on the bottom of the pan over the butter.
Dump the peaches including the juice into the pan, spread evenly. Spread the cake mix evenly over the peaches. Cut the 1 ½ sticks of butter into small pieces and place evenly over top of the cake mix.
Bake for 45 minutes to 1 hour, or until the top is golden brown.