Fudgy Chocolate Cake and Chocolate Espresso Frosting

Cake:
2 c sugar
1 1/2 c cake flour (Swans Down cake flour)
3/4 tsp baking soda
1/2 tsp salt
1 c water
2 Tbs instant espresso powder (Medaglia d'Oro)
4 oz unsweetened chocolate (Baker's 100% cacao* bar)
1/2 c vegetable oil
1/2 c sour cream (substituted Tofutti Sour Supreme non-dairy, lactose free Better Than Sour Cream)
2 eggs
1 1/2 tsp Mexican vanilla extract

Frosting:
1 c whipping cream (substituted Silk non-dairy creamer)
1/2 c butter (substituted 5-6 marshmallows)
1/3 c sugar
1/4 c water
2 tsp instant espresso powder
1/4 tsp salt
16 oz semisweet chocolate (Baker's dairy-free semisweet chocolate* bar)
1 tsp vanilla extract

Preparing cake:
Preheat oven to 325°F. Oil and flour two 9-inch round cake pans with 2-inch-high sides or use cupcake liners (makes 20-25 cupcakes).

Whisk first 4 ingredients in large bowl to blend. Bring 1 cup water to simmer in heavy small saucepan. Remove from heat. Add 2 tablespoons espresso powder; stir to dissolve. Add chocolate; whisk until chocolate is melted and smooth. Cool slightly.
In another large bowl, whisk vegetable oil, Better Than Sour Cream, eggs and vanilla to blend. Add chocolate mixture and whisk to blend well. Add 1/3 of chocolate-sour cream mixture to dry ingredients and whisk to blend. Add remaining chocolate-sour cream mixture in 2 more additions, whisking well after each addition. Divide batter equally between prepared pans. Gently tap each filled pan atop counter to burst any air pockets.
Bake cakes until tester inserted into center comes out clean, about 40 minutes for cakes and 20 minutes for cupcakes. Let cool 5 minutes. Run knife around sides of cakes and turn out onto rack. Cool completely.
Preparing frosting:
Bring first 6 ingredients to simmer in heavy large saucepan over medium heat, stirring until marshmallows melt. Remove from heat. Add chocolate and whisk until melted and smooth. Whisk in vanilla. Pour frosting into large bowl; cool until thick enough to spread, stirring occasionally, about 3 hours.
Frost cakes or cupcakes. I found that by warming the frosting in the microwave for a few seconds before frosting the cupcakes that it was much easier to spread and it regained a pretty, glossy shine. (Can be prepared 1 day ahead. Cover and refrigerate. Bring to room temperature before serving.

*Although Baker's chocolate is dairy free, on the box it states that it is processed on equipment that processes milk. One friend has such a bad reaction to dairy that she won't risk it, however, I've never had reaction to it.

Here is the original recipe on Epicurious:
http://www.epicurious.com/recipes/food/views/105697