Rinse the mussels under cold running water in a colander. Discard any mussels with cracked shells or that remain open after a light tap. Remove the beard by pulling toward the hinge; scrub stubborn debris with a small brush. Soak in a bowl of cold water for 10 minutes to expel sand, then drain and rinse once more.

Aromatics & vegetables

Heat a large wide pot or deep skillet with a tight-fitting lid over medium heat. Add the butter and olive oil. When the butter foams, add the chopped shallots and sliced fennel (if using). Sauté for 3–4 minutes until softened and translucent, stirring so they don’t brown. Add the minced garlic and sauté 30–45 seconds until fragrant.

If using cherry tomatoes, add them now and cook 2 minutes to soften and release juices.

Liquids & seasoning

Pour in the white wine (or chosen liquid) and increase heat to medium-high. Use a wooden spoon to scrape any browned bits from the bottom of the pot. Let the liquid come to a simmer and reduce slightly for 1–2 minutes to concentrate flavor.

Stir in the sea salt, black pepper, and red pepper flakes (if using). Add the mussels to the pot and immediately cover with the lid.

Steam the mussels for 4–6 minutes, shaking the pot once or twice, until most mussels have opened. Stop cooking as soon as they open — continued cooking will toughen them. Discard any that remain tightly closed.

If you prefer a creamy broth, remove the lid and stir in the heavy cream; simmer uncovered 1 minute to warm through. Finish with lemon juice and two-thirds of the chopped parsley; taste and adjust seasoning if needed.

To serve

Ladle mussels and broth into warmed bowls or serve straight from the pot. Scatter remaining parsley over the top, add lemon wedges at the side, and serve with slices of crusty bread to soak up the broth.

Estimated plating: 250–300 g mussels per person. Discard any unopened mussels when eating.