Mint chocolate filled cupcakes

Now, these were fun to make, but I feel like things just went a little different than how the other recipes have gone. I might've put to much peppermint extract into the filling, and the frosting is just overpoweringly sweet. But overall they were alright.

So first off you might want to use a stand mixer, but you'll want to first cream your butter and sugars till it is very light and fluffy. Then beat in the egg and vanilla, whisk together the buttermilk and sour cream and set aside, {now I was really suspicious about putting in sour cream, but it made it taste...