This fiery soup originated in the central and southern regions of Thailand. The key to the recipe is the flavorful broth, made by combining canned chicken broth, shrimp shells, chiles, and seasonings. After the mixture cooks for 30 minutes, it's strained and the seasonings are discarded. Look for dried japones chiles in your supermarket or through produce companies such as Melissa's (800-588-0151 or www.melissas.com).
Peel the shrimp, reserving 6 shells; set shrimp aside. Heat the oil in a large Dutch oven over medium-high heat. Add the japones chiles and shrimp shells; sauté for 3 minutes or until the chiles are blackened. Add broth, and bring to a boil. Add galangal and next 5 ingredients (galangal through shallots). Cover, reduce heat to medium-low, and simmer 30 minutes.
Strain soup through a sieve into a bowl; discard solids. Return soup to pan. Increase heat to medium-high. Add shrimp and fish sauce; cook 2 minutes or until shrimp are done. Remove from heat; stir in lime juice. Sprinkle with cilantro leaves. Serve immediately.