Preheat the oven to 350°F and grease a 9 x 13-inch baking dish.
Prepare the yellow cake mix following the package directions.
Fold in the drained crushed pineapple and reserved juice.
Transfer the batter into the prepared pan.
Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
Poke and Fill
Let the cake cool for 10 to 15 minutes, then use the handle of a wooden spoon or a chopstick to poke holes all over the cake.
In a large bowl, whisk the banana pudding mix with the cold milk until slightly thickened but still pourable.
Pour the pudding into the holes in the cake.
Let the pudding set for 5 minutes, then spread whipped topping all over the cake.
Add the Toppings
Drizzle hot fudge sauce over the cake.
Sprinkle on the chopped walnuts and top with maraschino cherries.
Chill and Serve
Refrigerate the banana split cake for at least 2 hours so it can set.
Add the crushed waffle cone pieces.
Just before serving, slice the bananas and arrange them evenly over the top of the cake. You can add pineapple chunks and/or sprinkles too, if liked.
Notes
Drain the cherries: Extra cherry syrup can streak the whipped topping and make red puddles on the cake.
Wipe the knife between slices: Pudding and topping can drag over the next piece if the knife is coated.
Crush cones by hand: Larger hand-crushed cone pieces show on the topping. Fine crumbs just blend into the whipped topping, so don’t use a food processor or blender. You want small chunks, not powder.