Prepare the chocolate cake mix according to the box directions. Set aside.
Quarter the Oreos** and add the cookie pieces to the cake batter.
Pour the batter into a greased 9×13 pan. Bake as directed on the back of the box. The cake will most likely need an additional 10 minutes for baking, but check it often. When a toothpick inserted in the middle comes out clean, the cake is done.
Set the cake on a wire rack to cool. Cool the cake completely before putting the trifle together. I made my cake earlier in the day so it would be ready to go when I needed it.
For the filling:
In the bowl of a stand mixer, add the softened cream cheese, butter and peanut butter. Whip these ingredients together until they are well combined, about 1 minute.
Add the powdered sugar and beat for an additional 1-2 minutes.
Carefully fold in 8 ounces of the Cool Whip. (You'll use the remaining Cool Whip for layering in the trifle.)
Now you're ready to assemble the trifle.
Cut the cake into small pieces or cubes. Put a layer of cake in the bottom of the trifle dish. Spoon 1/2 of the cream cheese filling on top of the cake. Sprinkle with 1/3 of the peanut butter cups and Butterfinger bars. Put 1/2 of the reserved Cool Whip on top of the candy. Repeat the layers: cake, cream cheese filling, candy and Cool Whip. Then top with the remaining 1/3 of the candy pieces.
Depending on the size of your trifle dish, you may not be able to fit all of the ingredients in. We used all of our filling, but had about 1/4 of the cake leftover. As you prepare the trifle, be sure to leave enough room so that you can have two of each layer and it will look so pretty!
Refrigerate until serving. This can be made a day in advance.
**If your chocolate cake is already made up, feel free to add the Oreos into the trifle along with the chopped candies.The calories shown are based on the trifle serving 20, with 1 serving being 1/20 of the trifle. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**