Preheat oven to 350 degrees
Mix together cake mix and dry gelatin in a mixing bowl
Using an electric mixer, mix in the milk and eggs - one egg at a time - then the melted butter. Continue mixing until the batter is smooth. Then gently fold in the drained peaches.
Pour into a 9x13-inch baking dish. Bake for 35 minutes, or until a toothpick inserted comes out clean.
Let the cake cool on the counter. When it is cool to the touch, spread the frosting over the top.
While your cake is cooling, make your frosting. Beat the room temperature butter & cream cheese together until smooth.
Add the sugar to taste - start with 1/2 cup.
For additional peach flavor, add in the reserved 4 tbsp peach juice or more peach gelatin.