Prepare chocolate cake according to package directions, bake in a 9x13 pan, and remember to grease it.
Remove cake from oven and set aside to let it cool completely.
In a medium mixing bowl, add pudding, milk, and peppermint extract, start with one teaspoon of extract and add more to taste. Whisk for 2 minutes, I do this with a hand mixer, until pudding starts to thicken. Fold in Cool Whip. Leave in bowl and cover, set mousse in fridge until ready to use.
To layer the trifle, you can choose to either serve this is a large dish and alternate layers, or do the trifle in single servings like pictured.
Cut the cake into 8 pieces, each piece is one serving. Cut each cake square into cubes. Set the cubes into the bottom of your cup, top with 1 tablespoon of crushed candy canes, then top with 1/2 of the mousse.
Repeat with the remaining cups, candy canes, cake squares and mousse. If there is any extra mousse, divide it evenly among the 8 cups.
If you are eating them right away then top with whipped cream (homemade is best!) and crushed candy canes. You can store them in the fridge until ready to serve. If you are using whipped cream do not top until right before you are going to eat them.