Preheat oven to 350°F (175°C). Grease a 9×13-inch baking pan with butter or nonstick spray.
Pour crushed pineapple (with juice) evenly across the bottom of the pan.
Spoon apple pie filling on top of the pineapple and spread gently.
Sprinkle dry carrot cake mix evenly over the fruit layer. Do not stir.
Drizzle melted butter evenly across the top to cover as much of the mix as possible.
Sprinkle shredded coconut and chopped nuts for extra crunch and flavor (optional).
Bake for 35–40 minutes, or until the top is golden brown and a toothpick comes out clean.
Let the cake cool slightly before cutting or serving. Enjoy warm or at room temperature.