This delectable spinach, fish and mushroom dish is cooked in the shape of a tart and is best served hot, cut into generous wedges. A flavoursome crayfish sauce makes a good accompaniment.
Cook the spinach, in only the water clinging to its leaves after washing, for 5 minutes, until wilted. Drain, then rinse the spinach under cold running water. Drain well and squeeze out as much water as possible.
Melt 50g/2oz/¼ cup of the butter in a pan, add the onion and fry for 5 minutes until softened. Add the mushrooms and cook until any liquid that the mu