Heat olive oil in a large pot over medium heat.

Add onions, garlic, fennel, leeks, and carrots to the pot.

Cook, stirring frequently, until the vegetables are softened but not browned.

Add red pepper flakes, saffron (or turmeric), thyme, bay leaf, fish broth, white wine, crushed tomatoes, salt, and pepper.

Bring the mixture to a boil, then reduce heat and simmer for 5 minutes.

Add diced potatoes to the soup.

Bring the soup to a simmer, cover, and cook for 10 minutes, or until potatoes are tender.

Add the cubed fish and scallops to the soup.

Simmer for 3 minutes, until the fish and scallops are cooked through.

Stir in the cream and bring to a simmer. Do not boil.

Remove the soup from the heat and stir in fresh basil or parsley.

Serve immediately with Parmesan croutons.