Stephen Ceideburg 1/2 lb Small fresh shrimp shelled -(shells reserved) and -deveined 2 qt Chicken stock 2 Green Serrano chilies, -seeded and chopped 1 ts Salt Grated zest of one lime 4 Kaffir lime leaves 3 Lemon grass stalks, cut into -1-inch pieces 1/2 lb Scallops 2 tb Fish sauce Juice of 3 limes 3 To 4 tablespoons fresh -cilantro, chopped 1 Red Serrano chili, seeded -and slivered 6 Shiitake mushrooms, sliced 2 Green onions, sliced -julienne Combine shrimp shells with stock, chilies, salt, lime, zest, lime leaves and lemon grass stalks in heavy nonaluminum pot. Bring to a boil, reduce heat, cover and simmer 20 to 20 minutes. Strain. Return liquid to pot and place over medium-high heat and bring to a boil. Add shrimp and scallops and cook 1 minute. Stir in fish sauce and juice of limes. Add chopped cilantro, slivered red chili and shiitake slices, and green onions. Stir and pour into a tureen or ladle into individual bowls.