These ingredients are found in Asian groceries:
Remove the heads and carapace of the shrimp and place them in a saucepan of water with salt, half of the galangal, lemongrass and lime leaves.
Boil about 15 minutes then strain the broth and add salt if necessary. Keep the shrimp aside.
Heat some coconut oil in a frying pan. Very finely chop the garlic, chili, remaining galangal, lemongrass and lime leaves and sauté them in the pan about 2 minutes.
Add the chopped shrimp for 2-3 minutes over medium-high heat. They should be just cooked. Set aside.
Put some of the broth in the pan and pour it in with the rest of the broth.
At the time of serving, place shrimp in a bowl and add broth. You can put in fresh herbs.