Refr Fiachson of the Kingdom of An Tir knows how Vikings eat, and he shares his knowledge of Norse cooking on his blog, The Viking Food Guy - Recreating the food and drink of the Viking Age (and others).
On his blog, Refr Fiachson ponders what he will eat at the An Tir West War. The answer is easy: Fish for breakfast!
One thing I’m definitely planning for is fish for breakfast. I’m a great believer in eating sea creatures first thing in the morning. Kippers, pickled herring, gravlax, lox, smoked salmon or trout… All such a treat in the AM. However, one of the people we camp with pretty regularly is a fish-o-phobe, so we try to keep it down for her sake. She’s not coming to the War, though, so my friend Eulalia suggested we stage a cultural exchange fish breakfast one morning. She does 13th C English recreation, which should be a little different from Viking-style fish breakfast.