Okay, so have you ever been in a sweets shop and like everything looks tasty and you get overwhelmed because you can't decide what to buy?  Maybe that's just me...any who, on my most recent visit to a cupcake shop in NY I bought a filled cupcake for like four dollars and it looked super good but then when I went to try it I was severely disappointed.  It was like WAY too sweet and somehow even though it was filled it was still dry.  AND IT WAS FOUR DOLLARS.  So that is what has led me to this post!
Double Chocolate Filled Cupcakes!

I'm not going to post a recipe for the actual cupcakes since I cheated and used Duncan Hines Dark Chocolate Cake Mix©.

But here's what I used for the filling and frosting. I tend to not do a good job when I'm measuring but I will give this my best guess...
6TB unsalted butter (softened)
3TB shortening
1/2 Cup marshmallow cream
3TB cocoa
2 (ish) cups powdered sugar
1/4 cup heavy cream
1 ts vanilla

Basically all I did was beat the first three ingredients until it was smooth with no lumps. Next add the vanilla.  After that I alternated the remaining dry ingredients and cream.  I whipped all of this until it was a bit more fluffy and then put it in a pastry bag with a plain circular tip.  Shove the tip into the top (some people do bottom-right through the paper) and push about a tablespoon of filling into the cupcake.  Then frost the tops and decorate!
Mine looked like this on the inside!

Oh! On another note for a full batch of cupcakes you may need to double or even triple that frosting recipe.  I only made 6 cupcakes and I have some leftover but it's definitely not enough for 24.  Thanks guys :]