Scrub mussels and clams in a large bowl of cold water. Remove beards from mussels and discard any broken or unopened shells. Use a damp cloth to ensure they are fully cleaned.

Remove from water and store in a large bowl covered with plastic wrap. Refrigerate until ready to use.

Place a large stockpot (or Dutch oven) on the stove over medium heat. Add olive oil.

When the olive oil is hot, add shallots and fresh herbs, if using. Sauté shallots until translucent, about 5 minutes.

Add broth, white wine, garlic, and salt and pepper to taste; bring to a gentle simmer.

Add mussels, clams, and parsley and cover the pot with a lid; cook shells until they open, about 5 minutes. Shake the pan once or twice during cooking, keeping the lid on, to distribute the mussels and clams.

Open the lid after 5-7 minutes and check if the shells are open. If not, cover and cook for an additional 1-2 minutes. Discard any mussels that haven't opened after this time.

Serve hot! Sprinkle with chopped parsley and serve in a bowl with crusty bread.