Place all the aromatics from "A" (the soup stock) and the water in a large saucepan on high heat.
When the water is boiling, immerse the whole fish in, don't worry if it's not fully submerged. Simmer for 10 minutes, turning the fish over if it's not fully covered.
Using a pair of tongs, take the fish out and leave to cool slightly on a plate, then flake the flesh off and leave aside.
Strain the stock into a clean saucepan and leave until needed.
Place the onion, garlic, ginger and lemongrass into a food chopper and zap it into a coarse grind. Or chop everything finely by hand, if you prefer.
Heat the oil in a frying pan or wok on medium heat and fry the chopped onion mix along with the chilli paste/powder and turmeric for a few minutes until you get a lovely aroma from the mix.
Then add the flaked fish to this mix and cook for a couple more minutes for the fish to absorb all those lovely flavours. Then take off heat.
Bring the soup stock back to boil and add the above fish and aromatics mix and stir to mix.
Mix the chickpea and rice flours with a little water to form a paste and add to the soup. Add the salt and fish sauce and leave everything to simmer for about 20 minutes. You could thicken it further to taste, with more of the flour, if you like. Don't forget to check seasoning and adjust accordingly with more fish sauce if necessary.
Serving Up
We are now going to blanch the noodles then dish up. Bring a large pot of water to a simmer.
If using dried noodles, follow packet instructions to soften, which usually involves soaking them for 15 minutes or so first.
Have a large Chinese strainer/skimmer at hand or a spaghetti fork. Place the noodles in the simmering water and cook for just 1 minute and remove. Divide the noodles up into the four bowls.
Top each bowl with the soup and I suggest that you let everyone help theselves to the garnishes and condiments they'd like on.
That's it! I hope you enjoyed the recipe and video!