Move the oven rack to the middle position and preheat the oven to 350 degrees F.
Spray a small rimmed baking sheet with cooking spray **see notes.
In a large bowl, beat together cake mix, water, oil, and eggs until smooth.
Spread the batter evenly into the baking sheet.
Bake for 12-15 minutes or until a toothpick inserted in the center comes out clean.
Remove the cake from the oven and cool on a cooling rack until completely cooled.
MAKE PUDDING:
Meanwhile, in a medium bowl, whisk together pudding mix and milk until smooth.
Add several drops of orange food coloring and whisk until well combined.
Place pudding in the refrigerator for 10-15 minutes or until completely set.
ASSEMBLE:
Remove pudding and whipped topping from the refrigerator.
Fit two pastry bags with large round tips.
Add pudding in one bag, and in the other, add whipping topping **see notes.
Using the rim of your trifle dish as a pattern, lightly press it into the cake.
Remove and then use the sharp knife to cut out the circle. You may need to cut it a little smaller so it fits into the trifle dish easily.
Add cake to the trifle dish.
Then pipe in the pudding.
Next, add Cool Whip on top of the pudding.
Decorate with sprinkles and candy, if desired.
SERVE:
Serve immediately or store in the refrigerator up to 1 day before serving.
Notes
Trifle Dish/Containers: Any container will work, but glass is best so you can see the layers. The number of servings you get will depend on the size of your container. I used small-footed trifles and got five servings with leftover cake.
Baking Sheet: You can also bake the cake in a 13x9 pan; the cake layer will be thicker in your container. You can also break up the cake into small pieces instead of cutting it into circles.
Pastry Bag: You can use a spoon to add pudding and whipped topping to the trifle; however, using a pastry bag makes the process easy.