Heat 2 tablespoons of oil. Sauté one half onion, crushed garlic, crushed shallot and tomato paste over low heat until fragrant. Add seasoning and simmer for 10 minutes. Then strain.
Defrost shrimps. Rinse and wipe dry. Cut open and devein. Sprinkle with caltrop starch. Scald in oil over medium heat.
Heat earthen pot. Add 1 tablespoon of oil. Sauté shallot until fragrant. Put in sauce, lemongrass shreds, onion, celery and shrimps. Simmer until shrimps are cooked. Add coconut juice. Try the taste. Put in chili shreds and Chinese parsley. Serve in pot with bread.