Old Fashioned Chocolate Cake with Mocha Chocolate Sour Cream Frosting

I made a "Heavenly" chocolate cake with a mocha chocolate frosting this past weekend. The same thing happened this time around as the last time with the cake doming in the middleand making it hard to get four good layers. I made it work but think I will make the buttermilk chocolate cake when I am making chocolate cake in the future. I had a point in making the frosting where I thought it was ruined. The recipe called for instant espresso powder and I decided to use a shot of espresso rather than the powder. The second I put the espresso into the smooth melted chocolate it dried up and the texture was no longer smooth and silky. I added the mixture to the butter and eventually the frosting creamed back up and smoothed on the cake beautifully. I attempted white chocolate curls for the first time and they became white chocolate shavings...I read how to do the curls in another cookbook and will have to practice!!