Combine all Café de Paris ingredients except the butter in a bowl and set aside for 4 hours.
Beat the butter until fluffy, mix with the infused ingredients, shape into a 2.5cm log using cling film, and chill.
Heat wine, shallots, garlic, and thyme in a saucepan for 3 minutes over low heat.
Add shellfish, cover, and cook for 3 minutes until shells open, discarding any that remain closed.
Strain the mixture, reserving the juices, and remove shellfish from shells while keeping a few for garnish.
Reduce the reserved juices in a pan over high heat until only 60ml remains.
Sauté the seasoned salmon in 15ml of Café de Paris butter and olive oil for 3 minutes per side.
Whisk reduced juices, 30ml Café de Paris butter, unsalted butter, and passata in the fish pan to emulsify.
Add the prepared shellfish, shrimps, and scallops to the sauce and warm through.
Serve the salmon topped with shellfish butter, garnished with whole shells and steamed potatoes.