To roast peanuts: Preheat the oven to 350°F (180°C). Place peanuts on a baking sheet and spread them out into one layer and roast for 15-20 minutes. After 10 minutes, stir the peanuts around. Check them often once they are close to finish, they burn fast! Remove from oven after they have turned golden brown. Once they are cool, grind them into a coarse meal (not peanut butter!) in a mortar and pestle or a food processor.
Note: If you have extra roasted peanuts, store them in the fridge to prevent them from going rancid. For even longer storage, put them in the freezer.
Make the curry paste: Cut chilies into chunks with scissors and remove all the seeds. Grind into a powder in a coffee grinder along with the coriander seeds. In a mortar and pestle, pound together shallots, garlic, ground chilies and coriander into a paste (does not have to be super fine).
Make the dressing: In a small pot, add ¼ cup of the coconut milk and bring to a boil. Add the curry paste and cook, stirring constantly, until it is reduced and thick. Once it is thick, continue to cook the paste for one more minute, adding a splash of coconut milk as needed if things are sticking to the bottom.
Add the remaining coconut milk, water, ground roasted peanuts, tamarind, palm sugar, and salt. Simmer the dressing for 20-30 minutes over low heat, until the dressing has the desired consistency, scraping the bottom frequently to prevent it from scorching.
If the dressing is too thick, feel free to thin it out a bit with water. Taste and adjust seasoning as needed, making sure it’s got a strong flavour since it will be served with lots of veggies. Let the dressing cool down slightly before pouring over the salad, but it should still be warm.
Tip: I made the dressing quite thick in the video because I like the richness of a thick dressing, but in Thailand, some people make the dressing quite thin so that you can toss the salad in it. If you prefer a thinner dressing, you can just add more water or more coconut milk to achieve a desired consistency, and you may have to increase the amount of seasoning accordingly.