Preheat and Prepare: First, preheat your oven to 180°C (160°C Fan / Gas Mark 4). Lightly grease a 9x13 inch (23x33 cm) baking dish with a little butter or cooking spray.

Create the Fruit Base: Spread the well-drained crushed pineapple evenly across the bottom of the prepared dish. This will be our juicy first layer.

Add the Bananas and Cherries: Arrange the sliced bananas in a single layer over the pineapple. Then, scatter the halved maraschino cherries evenly over the bananas.

Sprinkle the Cake Mix: Open the box of yellow cake mix and sprinkle the dry mix as evenly as possible over the fruit layers. Try to cover all the fruit right to the edges of the dish.

Add the Nuts and Chocolate: Scatter the chopped walnuts and chocolate chips over the dry cake mix.

Drizzle with Butter: Slowly and evenly drizzle the melted butter all over the top of the cake mix. I find that this is the most crucial step for a perfect topping. Try to cover as much of the dry mix as you can to ensure it all bakes into a golden, buttery crust.

Bake Until Golden: Place the dish in the preheated oven and bake for 45-55 minutes. You'll know it's ready when the top is a deep golden brown and the fruit juices are bubbling vigorously around the edges.

Rest and Garnish: Remove the cake from the oven and let it rest for at least 15 minutes before serving. This allows the molten fruit layer to set up a bit. Just before serving, add a flourish of rainbow sprinkles if you’re using them.