Clean and trim the fillets of plaice. Place cleaned mussels into a big saucepan with the dry white wine and place on to the heat until all the mussels are open. Discard any that do not open. Save the juice and strain into a clean saucepan. Pick the mussels from the shells and put to one side. Sweat the shallots in a little olive oil with the saffron and add vinegar and white wine. Reduce by half. Add olive oil and season, put to one side.

Roll the plaice fillets loosely and put them into a very hot nonstick pan and cook until golden brown on both sides. Season. Warm spinach through with a little of the dressing. Place a small amount of spinach into the centre of the plates.

Warm the vinaigrette and add the chopped tomatoes, courgette and chives. Spoon around the spinach and place the fish on top of the spinach.