Preheat the oven to 350°F (180°C). Line 2 12-cup cupcake tins with paper liners.
OPTION 1: If using prepared mix, in a medium bowl, whisk together the cake mix, water, oil, and eggs.
OPTION 2: If making the cupcake batter from scratch, in a small bowl, whisk together the cocoa powder and boiling water until the cocoa powder is completely dissolved. In a large bowl, combine the flour, sugar, eggs, vegetable oil, milk, cocoa mixture, baking soda, salt and vanilla extract.
Fill the cupcake cups halfway with batter.
Bake for 18–21 minutes, or until a toothpick inserted in the center of a cupcake comes out clean. Let the cupcakes cool completely before decorating.
Using a large piping tip, poke a hole in the center of each cupcake. Discard the scraps or save for another use.Fill each hole with the sprinkles.
Top each cupcake with chocolate frosting, a drizzle of chocolate, and a maraschino cherry.