Fish sauce, also called nuoc mam or nam pla, is made from fermented fish and salt. I thought it would be interesting to try to come up with a vegan alternative.
My pal Marie from Meandering Eats suggested that the key taste to capture was umami, the savory taste found in soy-based foods.
I took seaweed, soaked it, added miso for the salty umami flavor, and blended it. It has a briny taste that is a pretty reasonable substitute for fish sauce.
Note that the final product is not particularly appetizing in color, so you might want to keep this a secret ingredient in your recipes.