Preheat oven to 350 F. Get out two muffin or cupcake trays and place a liner in each of the 24 spots.
Cream butter and sugars together until fluffy. Beat in eggs and vanilla.
In a small pan stir water, chocolate and espresso powder over low heat until melted. Allow to cool slightly before beating into butter mixture.
Sift together flour, cocoa powder, baking soda, and salt and stir into batter alternately with sour cream.
Divide the batter evenly between the 2 muffin tins. I use a 1/4 cup measure to scoop, but each scoop is not a full 1/4 cup. You kind of have to eyeball it and then when all the batter is gone, look at the cupcakes and try to even them out if some got more or less. You dont want more than 1/4 cup for each cupcake because they will puff up too big then. You want them to just come to the top of the liner once they are baked.
and bake for 13 - 15 minutes, until a tester/toothpick inserted in the center of one of the cupcakes comes out clean.
Allow to cool at least 15 minutes in the tins, then scoop each cupcake out onto a plate to cool completely. FOR THE FROSTING:
In large bowl, beat shortening and butter with a mixer until light and fluffy. Beat in vanilla.
Gradually add the sugar, one cup at a time, beating well on medium speed. Scrape the sides and bottom of the bowl often. When all the sugar has been mixed in, icing will appear dry.
Gradually add 2 tbsp of the milk; beat at medium speed until light and fluffy. If you need to, add a bit more milk.
For Pure White Icing, omit the butter and substitute with an additional 1/2 cup shortening instead of the butter and add 1/2 teaspoon No-Color Butter Flavor. You can find the Butter Flavoring at any cake store.