1. Chop palm sugar and add to a pan with 2 tbsp water. Simmer until melted.
2. Toast dried shrimp in a dry pan for 3–4 minutes until fragrant and softened.
3. Crush half the shrimp, keep the rest whole.
4. Add fish sauce to the melted sugar and simmer for 1 minute.
5. Add crushed shrimp, whole shrimp, shallots, chilies, and chili flakes. Let bubble for a few minutes.
6. Stir in crispy shallots and cook another minute.
7. Cool until thick and sticky.
8. Serve with sour mango or store in the fridge (lasts about 2 weeks).