Peel and wash the potatoes and cook them in salted water for 20 minutes. Wash the fish, pat dry, drizzle with lemon juice, salt and pepper. Turn the fish in the flour. Heat the oil in a pan and fry the fish until golden on both sides over medium heat.
Bring approx. 200 ml of water to the boil in a large saucepan. Steam the spinach in it and turn it until it has collapsed. Toss in a little butter in a pan and season with salt, pepper and nutmeg.
Drain the potatoes and sprinkle with parsley. Arrange everything on 4 plates and serve.