In a Dutch oven, saute onion in oil until tender. Add the broth, water, brown sugar, ginger, fish sauce, curry paste and lemongrass. Bring to a boil. Reduce heat; carefully stir in shrimp and edamame. Cook, uncovered, for 5-6 minutes or until shrimp turn pink., Add the coconut milk, corn, bamboo shoots, basil, cilantro, lime juice, lime zest and curry powder; heat through. Discard lemongrass.