Fish sauce probably doesn't rank up there with bacon and salami as an animal product that veg*ns desperately miss the flavour of. Nevertheless, it does pop up in recipes that otherwise look delicious and veg-friendly. I came across one such recipe this week and rapidly turned up a vegan fish sauce substitute to try it out with.
The sauce recipe uses wakame (I substituted dulse flakes) and mushroom 'oyster' sauce for a taste of the sea, plus garlic and miso for extra umami. Everything's boiled down to a barely-palatable concentrate. I'm not confident that it resembles fish sauce, precisely, but it certainly has pungency in common with its namesake!
Vegan fish sauce
(adapted slightly from a recipe on The Kitchn)
1 tablespoon dulse flakes
3 cloves garlic, roughly chopped
2 teaspoons peppercorns
3 cups water
1/2 cup mushroom 'oyster' sauce
2 teaspoons miso
Place the dulse flakes, garlic, peppercorns and water in a saucepan and bring them to the boil. Turn down the heat and simmer them for 20 minutes. Strain the liquid, discarding the solids and returning the liquid to the saucepan. Add the 'oyster' sauce and boil it down until it's reduced by half, about 40 minutes. Turn off the heat and stir in the miso. Store the sauce in the fridge.