Preheat your oven to 350°F (175°C).
Grease the bottom and sides of a 9×13 inch baking dish with butter or non-stick cooking spray.
Spread the two cans of cherry pie filling evenly across the bottom of the dish, ensuring the fruit reaches all four corners.
Sprinkle the dry cake mix evenly over the cherry layer. Do not stir the mixture; use a spatula to gently level the powder so it covers the cherries completely.
Arrange the thin slices of cold butter over the top of the cake mix, covering as much surface area as possible to ensure the dry mix absorbs the fat.
Scatter the chocolate chips or slivered almonds over the top if you are using them.
Bake for 30 to 35 minutes in the center rack of the oven.
The dessert is ready when the edges are bubbling and the top appears set with a slight crust. A toothpick inserted into the center should come out with a few moist crumbs but no raw batter.
Allow the cake to cool for at least 10 minutes before serving to let the juices thicken.