How to Make It
Preheat the oven to 400°. Prick the potato all over and bake for about 40 minutes, or until tender. Let the potato cool slightly, then peel and coarsely grate enough to yield 1 cup; eat the rest.
Heat the peanut oil in a large stockpot. Add the onion, celery, green bell pepper, carrot and ham and sauté over moderately high heat until the vegetables are wilted, 4 to 5 minutes. Add the shrimp, peanuts, parsley, garlic, salt, Old Bay Seasoning and bay leaf and sauté for 3 more minutes. Add the grated potato, fish stock and milk and bring just to a boil. Whisk in the cornstarch mixture and return to a boil. Lower the heat and simmer for 40 minutes. Discard the bay leaf and let the soup cool for 20 minutes.
Working in batches, puree the soup with the spinach leaves in a blender or food processor until smooth. Strain the pureed soup into a large saucepan.
To serve, gently reheat the soup over moderate heat. Add the crabmeat and warm for 1 minute. Ladle the soup into shallow bowls and garnish each serving with a Country Ham Crouton.