1. Prepare seafood dipping sauce : Grind chilies, garlics and coriander roots in a mortar and pound until mixed thoroughly (or using food processor). Then mix with lime juice, fish sauce, sugar and salt. Stir until sugar dissolved and all ingredients mixed well. Transfer to a dipping sauce bowl.
2. Wash and clean shrimps. Set aside.
3. Heat water in a pot over medium heat. Add lemon grasses, galangals, kaffir lime leaves, and basil leaves.
4. Wait until boiling, add shrimps. When shrimps are cooked. Remove from heat and drain.
5. Transfer shrimps to a serving plate. Serve immediately with seafood dipping sauce and hot steamed rice.