Pro tip: fold fresh blueberries into the filling if you have them, it will add pops of fresh berry flavor throughout. The recipe combines a can of cherry pie filling with a can of pineapple tidbits, ...
Now spoon the cake mix into the prepared tin, level off the top with the back of a spoon, then sprinkle over the remaining third of the cherries and poke them just under the surface with a teaspoon.