Preheat the oven to 325
Mix cake mix and water on medium high until well combined and fluffy.
Pour into a greased twinkie baking dish, making sure not to go over half full. (Using a Piping bag makes this super easy)
Bake for 20-25 mins or until golden brown.
Remove from oven and immediately turn out onto a parchment lined baking sheet.
Repeat the process for the next 2 batches.
While the twinkies are cooling, make the frosting.
Mix marshmallow fluff, shortening and vanilla until smooth.
Gradually add in the powdered sugar and lastly add in the 2 tbsp water.
Add filling to a piping bag fitted with tip 230 (made for adding fillings to cupcakes)
Flip all of the twinkies over.
Make three holes in the bottom, squeeze in a little filling.
If you hold the twinkies in your hand you can actually feel the cake filling up. If you over fill them it will leak out. Use an offset spatula or a butter knife to wipe off any excess.