Bake the cake in a 9x13 inch pan according to package directions. Line the bottom of the pan with parchment paper and lightly grease. Bake according to package directions. After cake has cooled for 20 minutes to half an hour, invert cake onto a cooling rack to cool completely.
With a cake cutting wire, slice the cake in half. Spread an even layer of the carvel crunchie mixture over the bottom layer of cake. Top with the top of the cut cake. Frost entire outside of cake with the Hersheys chocolate frosting recipe.
Using the tinted buttercream frosting (I used green, blue and white), accent the borders of the cake. Sprinkle the silver sprinkles around the outer edge of the cake.
Using the blue sparkle decorators gel, make the "A" for Avengers. In each of the four corners, place a clip art picture of one of the Avenger characters. (i did a google search, printed out the pictures, colored them and pasted them on the back of wax paper before placing them on the cake).
Notes
For the Cupcakes:1. Cook the cupcakes according to package directions. Allow the cupcakes to cool completely before frosting.2. Frost each cupcake using the Hershey's chocolate frosting recipe. Sprinkle silver sprinkles over the top of each cupcake, then top each cupcake with an Oreo.3. With the blue sparkle decorators gel, make an "A" for Avengers.