1. In a large glass or plastic mixing bowl, whisk together egg yolks and sugar; set aside.
2. In a medium saucepan, combine Guinness and 1 1/4 cups heavy cream. Cook over medium heat, whisking often, until the edges just begin to bubble. Remove pot from the heat, and add chocolate to pot; whisk until smooth.
3. Slowly pour the chocolate mixture into the egg yolk mixture, whisking constantly while streaming the chocolate into the bowl. After the pudding base is combined, return pudding to saucepan and return the medium-low heat. Cook, whisking constantly, until the pudding thickens and coats the back of a spoon.
4. Divide pudding among serving bowls/jars/whatever you're using and cover with plastic wrap. Place pudding in fridge until pudding is chilled and set.

Jameson Whipped Cream:

1. In a medium bowl, add all whipped cream ingredients. Beat on medium speed until stiff peaks form. Spoon whipped cream onto top of chilled pudding. Sprinkle with cocoa powder, if desired.