Venetian Crab Soup

Preparation Heat oil in a wide 6-quart heavy pot over medium heat until it shimmers. Cook onion, celery, and fennel, stirring occasionally, until golden, 8 to 10 minutes. Add shrimp shells and cook, stirring occasionally, until shells turn pink. Stir in tomatoes with their juice. Simmer, breaking up tomatoes slightly with a wooden spoon, 3 minutes, then add ginger, saffron, curry powder, and bay leaf and simmer 5 minutes. Add chicken stock and boil uncovered 5 minutes. Reduce heat and simmer uncovered 45 minutes. Discard bay leaf, then purée soup (including shrimp shells) in batches in a blender until finely ground, about 2 minutes per batch (use caution when blending hot liquids). Strain soup through a fine-mesh sieve into a clean pot, discarding solids. Peel and dice potato. Peel and dice enough celery root to measure 1/2 cup. Add potato and celery root to soup and gently simmer uncovered until tender, about 10 minutes. Remove from heat and stir in butter and crabmeat. Season with salt and pepper.

Preparation Heat oil in a wide 6-quart heavy pot over medium heat until it shimmers. Cook onion, celery, and fennel, stirring occasionally, until golden, 8 to 10 minutes. Add shrimp shells and cook, stirring occasionally, until shells turn pink. Stir in tomatoes with their juice. Simmer, breaking up tomatoes slightly with a wooden spoon, 3 minutes, then add ginger, saffron, curry powder, and bay leaf and simmer 5 minutes. Add chicken stock and boil uncovered 5 minutes. Reduce heat and simmer uncovered 45 minutes. Discard bay leaf, then purée soup (including shrimp shells) in batches in a blender until finely ground, about 2 minutes per batch (use caution when blending hot liquids). Strain soup through a fine-mesh sieve into a clean pot, discarding solids. Peel and dice potato. Peel and dice enough celery root to measure 1/2 cup. Add potato and celery root to soup and gently simmer uncovered until tender, about 10 minutes. Remove from heat and stir in butter and crabmeat. Season with salt and pepper.