In saucepan, sweat tomato with garlic and chili in butter, then add shrimp paste, add sachet of white turmeric, lemongrass, star anise, karen chili, and tamarind and reduce over low heat for about 2 hours.

Remove sachet, then blend prawn tomato bisque on high speed, pass, adjust seasoning with milk, tamarind water, dried karen chili powder, and light palm sugar as needed.

Before service, blend sauce daily with head fat of daily river prawns.