Total time: 50 minutes
Note: For the fish, use a white fish such as cod or halibut. Serrano ham is available at select gourmet markets and specialty stores.
1 egg, at room temperature
1/2 cup extra virgin olive oil
1/4 cup fresh lemon juice
2 quarts simple fish stock
1 1/2 cups diced boiling potatoes
1/4 cup shelled peas, fresh or frozen
1 1/2 cups chunks of raw fish
1/4 cup chopped Serrano ham
1/3 cup peeled shrimp (3 ounces)
1/4 cup dry sherry
Salt and pepper to taste
1. In the bowl of a blender, place the egg. With the motor running, add the oil in a slow stream until it is emulsified (it will thicken like a mayonnaise). Blend in the lemon juice, then set aside. (If the emulsion happens to "break" while it is blended, simply pour out the mixture and add a fresh egg white to the blender container. Add the mixture in a slow stream to fix the emulsion.)
2. In a large, heavy-bottomed soup pot, add the fish stock and bring to a boil over high heat. Add the potatoes, cover and simmer for 10 minutes, until somewhat softened but not cooked through. Add the peas and cook an additional 5 minutes.
3. Add the chunks of fish, ham, shrimp and sherry. Bring the soup to a boil, then reduce to a gentle simmer.
4. With the blender running, ladle about 1 cup of the hot broth from the soup into the emulsion in the blender and blend until smooth. Remove the soup from the heat and whisk the emulsion into the soup. Add salt and pepper to taste. Serve immediately. The soup can be reheated, but do not boil. This makes a generous 2½ quarts of soup.