Prepare the Topping:

Preheat the oven to 350°F (175°C) and grease a 9×13-inch baking pan.

Pour the melted unsalted butter into the bottom of the greased pan and sprinkle the brown sugar evenly over it.

Spread the cherry pie filling on top of the brown sugar layer, distributing it evenly.

Make the Cake Batter:

In a large bowl, add the chocolate cake mix, eggs, vegetable oil, water, and vanilla extract.

Mix until the batter is smooth and all ingredients are fully incorporated.

Assemble the Cake:

Gently pour the prepared batter over the cherry pie filling, spreading it out evenly with a spatula.

Bake:

Place the pan in the preheated oven and bake for 35 to 40 minutes, or until a toothpick inserted in the center comes out clean.

Cool and Invert:

Let the cake cool in the pan for about 10 minutes.

Then, place a large serving plate or platter over the top and carefully flip the pan to invert the cake.

Serve warm or at room temperature.