Oh Alex...THIS is why I am in the business I am in today.
My mother was the QUEEN of whoopies on the west coast and I use her TNT recipe to this day (and have added a few extra special touches, to make it unique) in my gourmet stuffed dessert business.
Also known as Gobs in other parts of the country, they are little pillows of heaven (and about a bazillion calories...). Chocolate cake "stuffed" with a creamy, sugary goop of goodness...mmmm mmmm mmmmmmmmmmm.
My business name and idea stemmed from this very item and has expanded into much more (stuffed cupcakes, cookies, fruits, brownies, chocolates, truffles, just about anything), but this is why I am what I am today.
Another great source of whoopies is from wicked whoopies (although I do believe my mothers are far more superior).
Here is a little history on the whoops...
Whoopie Pie, Whoopie Pie History and Recipe