Remove the filling from the cookies and place in a small bowl. Place the cookies in a plastic zip-top bag. 

Crush the cookies thoroughly by pounding with a heavy pan, rolling pin or meat pounder. The crumbs should be no larger than the size of a pea. Place the cookie crumbs in a medium mixing bowl.

Add the peanut butter and 2 tablespoons of hot water to the cookie crumbs and mix, kneading the dough to incorporate all of the peanut butter and water. If the dough is too dry to stick together, add another tablespoon of hot water. 

Form the dough into a smooth, softball-sized sphere, adding a few whole Whopper candies to the middle if desired. Set the cake sphere onto a plate and press down gently to flatten out the bottom, leaving the top as rounded as possible.

Add the powdered hot cocoa mix and 1 tablespoon of hot water to the bowl with the cookie filling and whisk until smooth. If the frosting is too thick, carefully add additional hot water a small amount at a time, up to another tablespoon.

Drizzle the frosting over the top of the cake. Crush a few more Whoppers and sprinkle on top.