Chocolate Stout Cake

Ingredients

• Cake
• 2 cups stout beer (such as Guinness)
• 2 cups unsalted butter
• 1 1/2 cups unsweetened cocoa powder (preferably Dutch-process)
• 4 cups all-purpose flour
• 4 cups sugar
• 1 tablespoon baking soda
• 1 1/2 teaspoons salt
• 4 large eggs
• 1 1/3 cups sour cream
• Icing
• 2 cups whipping cream
• 1 lb bittersweet chocolate (not unsweetened) or 1 lb semisweet chocolate, chopped