Allow cupcakes to cool completely, about half an hour. Once cupcakes are cool, use a handheld electric mixer, or scoop softened chocolate mixture into the bowl of your stand mixer and use the whisk attachment, to whisk mixture on medium-high until light in color, about 2 minutes.
Using a serrated knife with a sharp tip, cut a cone-shaped piece out of the center of each cupcake. You don't have to be neat about it, and you can discard (or eat) the cone.
Transfer chocolate frosting to a plastic bag by placing the bag over an empty cup and scooping the mixture inside. Seal bag and snip off one of the corners. Use the bag to "pipe" chocolate mixture into the cupcakes and fill to the top.
Make sure to use grease-proof liners if grease spots matter to you. Regular liners hold up just fine for these cupcakes, but the butter in the graham cracker base will turn the liners dark, and doubling up only works long enough to snap a few photos. ;)