For The Frosting, Place The Cream In A Medium-Size Heavy Saucepan Over Medium Heat.
Bring To A Simmer, And Then Remove From The Heat.
Stir In The Chopped Chocolate, And Stir Until All The Chocolate Has Melted And The Mixture Is Smooth.
Pour The Icing Into A Stainless Steel Bowl, And Set Aside On The Counter Until Ready To Frost The Cake.
You Can Make This Up To 3 Hours In Advance.
For The Cake, Place A Rack In The Center Of The Oven, And Preheat The Oven To 350°F.
Grease And Flour Three 8″ Round Cake Pans That Are At Least 2″ Deep, And Shake Out The Excess Flour.
Set The Pans Aside.
Place The Stout And Butter In A Large Saucepan, And Stir Over Medium Heat Until The Butter Melts, 3 To 4 Minutes.
Whisk In The Cocoa Until Smooth.
Remove The Pan From The Heat And Let It Cool.
Place The Flour, Sugar, Baking Soda, And Salt In A Large Bowl, And Whisk To Combine.
Set Aside.
Place The Eggs And Sour Cream In A Large Bowl, And Blend With An Electric Mixer On Medium Speed Until Just Combined, 1 Minute.
Add The Chocolate And Butter Mixture And Blend Just To Combine.
Fold In The Flour Mixture, And Scrape Down The Sides Of The Bowl With A Rubber Spatula.
Divide The Batter Between The Prepared Pans, And Place The Pans In The Oven.
Bake The Cake Until The Top Springs Back When Lightly Pressed With A Finger, 30 To 35 Minutes.
Remove The Cake From The Oven, And Place The Pans On A Wire Rack To Cool For 10 Minutes.
Run A Knife Around The Edges Of The Pans, Give The Pans A Gentle Shake, And Invert The Layers Once And Then Again So The Layers Cool Completely Right Side Up, About 1 Hour.
To Assemble The Cake, Stir The Frosting Until Smooth Enough To Spread.
Place 1 Layer On A Cake Plate, And Spread With About â…” Cup Of Frosting.
Top With The Second Layer, And Spread With Another â…” Cup Of Frosting.
Top With The Third Layer And Spread The Top And Sides Of The Cake With The Remaining Frosting.
Slice And Serve.
