fisherman's soup

Ingredients
1 tablespoon olive oil
2 leeks (white and light green parts), cut into 1/4-inch-thick half-moons
2 cloves garlic, sliced
1 small fennel bulb, quartered and sliced
1/3 cup dry sherry
1 28-ounce can diced tomatoes
1/4 teaspoon crushed red pepper
Kosher salt
1 pound skinless halibut fillet or some other firm white fish, cut into 2-inch pieces
1/2 pound mussels, scrubbed
1 cup fresh flat-leaf parsley, roughly chopped
1/2 cup mixed olives

Directions
Heat the oil in a large saucepan over medium-high heat. Add the leeks, garlic, and fennel and cook, stirring occasionally, until they begin to soften, 3 to 4 minutes.
Add the sherry, tomatoes and their juices, red pepper, and 1 teaspoon salt and bring to a boil. Reduce heat and simmer for 15 minutes.
Add the fish and mussels and simmer gently until the fish is cooked through and the mussels have opened, 4 to 5 minutes. Stir in the parsley. Serve with the olives