Mix milk and chocolate pudding mix until smooth and refrigerate while you prepare the rest of the recipe. (I used less of a milk to pudding mix ratio than the instructions on the back of the box call for because I wanted a thicker pudding.)
Preheat oven to 350°F. Mix the 1/2 box of cake mix with egg whites, coffee, and yogurt and mix until all ingredients are well-integrated and no clumps remain. Note: this too is a departure from the traditional cake mix instructions on the box. No oil, no water, no problems – these modifications produce a pillowy-soft cupcake.
Grease 10-12 wells of a cupcake pan with cooking spray (depending on how much batter you have – I wasn’t precise with halving the cake mix box so I ended up with ten cupcakes and not twelve). Fill each well 3/4 full. Bake for 18-21 minutes or until tester inserted into tallest part comes out clean. Let cool to room temperature.
Once cupcakes have cooled, hollow out inside of each. I totally used this recipe as an excuse to go and buy a cupcake corer, but I’m sure a knife and a spoon will do the trick.
To fill the cupcake, layer 1-2 tbsp of chocolate pudding, a sprinkling (or more) of chopped chocolate, a drizzle of chocolate syrup, more chocolate pudding, etc. until filling is flush with cupcake edges. This isn’t an exact science – the best part is that you get to call the shots and add whichever ingredients you want, in the quantities you want, as you see fit.
Right before serving, place a dollop of whipped cream atop each cupcake and drizzle with chocolate syrup and remaining chopped chocolate.