Bone and skin the fillets. Cut into 8 equal portions. Arrange in a buttered baking pan. Season with salt and pepper. Pour the wine over. Cover with foil, and bake at 350 F (180 C) until flaky.
Blanch the spinach in salted boiling water. Drain and squeeze out excess of water. Mix a small amount of sauce into spinach. Spread the bottom of an oven proof serving dish with chopped spinach.
Arrange the fish on top, and pour the remaining sauce over. Sprinkle with cheese, and brown under a broiler.