To make the tomato water, blend the tomatoes and water to a thin consistency. Pour into a small saucepan, add salt, and bring to the boil. Reduce the heat to medium low and cook for 15 minutes.
To make the ginger water, pound the ginger with a pestle and mortar until broken down into a paste. Add the water and muddle around until combined.
For the sour water, add the water, vinegar, and jaggery to small saucepan and heat until the sugar is dissolved.
If your noodles are not completely fresh (i.e. made that day and never refrigerated), you will need to cook them briefly. To do this, bring a pot of water to a rapid boil. Use a noodle basket or a mesh strainer to dunk the noodles in the boiling pot before tipping into the serving bowls. Do this one portion at a time. If you haven’t already blanched the bean sprouts, you can do so using this same pot of boiling water.
Distribute the tomato water, sour water, and ginger water over the noodles. Add ground sesame seeds and peanuts, along with the prik jeow, fried garlic, and a slight drizzle of the black soy sauce. Top with the cabbage, blanched sprouts, and herbs.
Serve with additional salt and some MSG.