To serve, spread mayonnaise mixture on bottom bun, add burger, tomato and a portion of mesclun.

Gently fold the remaining shrimp and avocado cubes into the mayonnaise mixture.

Add the mayonnaise mixture and fold together to combine.

Pour the mayonnaise mixture back into the stock and reheat very gently, if necessary; do not boil.

Coat the flesh side of the fillets with the mayonnaise mixture and place on a baking sheet, skin side down.

Pour the mayonnaise mixture over the vegetables, toss to coat and refrigerate for at least 1/2 hour.

Serve with the mayonnaise mixture on the side and sprigs of cilantro for garnish.

Place bread on a work surface and spread each piece with mayonnaise mixture.

Cover the cut surface of each tomato with about a teaspoon of the mayonnaise mixture, mounding it slightly.

Place a mussel, well coated with the mayonnaise mixture, on each shell.