Prepare the four angled beans. Remove the tips on both ends. Cut slantingly into 1.5 to 2 inch pieces. Set them all aside.
Prepare the herbs to blend. Starting with the most fibrous herb, roughly chop the lemongrass into thin chunks. Set them aside.
Remove the stems from the red chillies and chop them roughly. Set aside.
Roughly chop the galangal into small, thin pieces. Set them aside.
If the shallots and garlic are large, cut them into halves or thirds. Set aside.
Keep the turmeric with the skin on, and with the tip of the knife, break it into half.
Add all the herbs into the blender, together with the chilli paste, washed dried shrimps, water and shrimp paste. Blend smooth and even in colour, for about 30 seconds.
Warm the cooking oil in a stainless steel pan over medium heat.
While the oil is still cool, add all the sambal mixture, scraping the blender to get it all out. Stir continuously until all the mixture has combined with the cooking oil.
When the sambal mixture is starting to boil, add the salt, sugar and concentrated tamarind water. Continuously stir for about 5 minutes, or until it becomes very thick and paste-like.
Spread the sambal as evenly as you can in the pan. Add all the angled beans and mix until they are well coated with the sambal paste. Add some water to help with this.
Continuously fry for 3 minutes for just-cooked, crunchy angled beans. For softer angled beans, fry for about 5 minutes.
Taste and adjust as preferred.
Switch off the heat and dish it out.
Enjoy with a plate of white rice.