Heat a frying pan with a lid until hot. Add the razor clams and wine and cover with the lid. Steam the razor clams for 1-2 minutes, or until they have opened. Discard any clams that have not opened. Pour the contents of the pan into a colander over a bowl.
Pull the razor clam flesh from the shells (discard the shells) and carefully wash to remove any grit. Remove the dark grey part (the stomach), found roughly running down the middle of each clam. Finely chop the razor clams.
To make the sauce vierge, place all but one tablespoon of the olive oil into a small pan over a low heat. Add the coriander seeds, shallots, garlic and chopped clams and cook for ten minutes, but do not boil.
Heat a separate frying pan until hot and add the remaining olive oil and the turbot fillets. Fry for 3-4 minutes on each side, or until just cooked through. Remove the turbot from the pan and place onto a plate to prevent them from cooking any further. Season, to taste, with salt and freshly ground black pepper and a little lemon juice.
To serve, remove the whole garlic clove from the sauce vierge, then stir in the chopped tomatoes, remaining lemon juice and parsley and return to the heat to warm through. Season, to taste with salt and freshly ground black pepper.
Place a turbot steak onto each serving plate and spoon the razor clam sauce vierge over the top.