This is a simple one- and was a standard menu item at the Deli Haus in Kenmore where I lived.
Best served with a Velvet Elvis (especially my modified version), mentioned elsewhere here...
Pour a Perfect Guinness (also elsewhere in this forum).
Add a scoop of vanilla or coffee ice cream- chocolate works well too, but my favorite? A dollup of peanut butter ice cream.
Enjoy.
Toldja it was simple.