Crumble the Chocolate Irish Stout Cake into bite-size pieces, into a large bowl. Depending on how many you plan on serving, have ready 6 – 10 pint or half-pint glasses. Place 1/4 cup of the cake crumbles in each glass.
Repeat with all the glasses, creating 3 layers in each glass. Wrap with plastic wrap if not serving right away. These can be made 24 hours in advance (refrigerated) and get better with time, as all of the flavors fuse together.