A simple recipe for vegan fish sauce using mushrooms, seaweed, garlic
Bring all to a simmer in a medium pot, uncovered, over medium heat. Simmer until reduced by half. You should have about 2 cups of liquid.
If you have time, let this steep over night, or up to 24 hours, covered on the counter. Then strain and pour into jar. If liquid is less that 2 cups, add water to make it 2 cups. This will ensure the right amount of saltiness.
Store in the fridge and use as you would fish sauce, one to one.