You can make a dump cake using real ingredients. Probably just as bad for you, but at least it doesn’t have the additives.
Find a pie recipe that uses real fruit, and follow the directions for the filling, but pour it in a cake pan instead. Then use your favorite yellow cake recipe, but leave out the wet ingredients. Sprinkle that on top of the pie filling. Melt a stick of butter, mix in the amount of vanilla extract that the cake recipe called for, and drizzle as evenly as possible on top of the dry cake mixture.
You may need to adjust the amount of butter, depending on how big a cake your recipe is for. But generally this works. Bake at 350 until the top is starting to brown and the filling is bubbly, usually 30-45 minutes.
Now that is so good to know, Ellendra—thank you!