I'd love to try and prepare the Ruby Noodles, but I can't find fish sauce where I live. Is there a way to substitute it with something else?
Nigella's Ruby Noodles (from COOK, EAT, REPEAT) are chilled noodles that have been initially cooked with beetroot (beet) juice to give colour and flavour. The noodles are dressed with a salty-sour mixture of soy sauce, fish sauce, sesame oil, brown rice vinegar and lime. Fish sauce is a fermented sauce that has a salty, umami-rich taste that is difficult to replicate, but if you can't find it then once the noodles are cooked we suggest adding an extra teaspoon of soy sauce instead of the two teaspoons of fish sauce to the warm noodles (so you would use a total of 1 tablespoon of soy sauce).
For the dressing, we would suggest omitting the fish sauce and just adjusting the lime, vinegar and soy sauce to suit your own taste. It may help to dip a cooled string of spaghetti in the dressing to taste, so that you get a feel for how the dressing will taste in combination with the pasta.