Cut soup vegetables, shallots, and garlic into fine cubes. Heat a large saucepan (at least 7.5 liters) over medium-high heat. Add a little oil, then fry the vegetables, shallots, and garlic for 2 minutes.
Deglaze the pan with 1 cup water. Add the vegetable juice and strained tomatoes. Add fish stock cube, salt, pepper, sherry, and Cremefine. Bring to a boil.
Place mussels in a large bowl of cold water and soak for 5-10 minutes. Remove any barnacles and the beards (thin stringy threads attached to the shell). Gently tap any open mussels under water; discard any that don't close or have cracked shells. Rinse thoroughly under cold running water.
Add all mussels to the boiling stock at once. Cook for 12 to 15 minutes until the mussel shells open. Discard any mussels that remain closed. Arrange the open mussels on a plate with the vegetables and broth. Sprinkle fresh parsley over the mussels and season to taste.