Cook the rice in boiling salted water for about 20 minutes. Wash fish, dab dry and cut into 8 strips. Sprinkle with lemon juice. Let marinate for about 10 minutes. Sort the spinach and wash it thoroughly.
Clean, wash and dry mushrooms. Heat 1 teaspoon of fat in a pan. Fry the mushrooms in it. Season with salt and pepper. Remove and put aside. Pour the vegetable stock and milk into the frying fat and let it thicken slightly over a high heat.
Bring wine and 1/8 litre water to the boil. Salt salmon fillets and stew them for 6-8 minutes at low heat. Allow the sauce to combine with the egg yolk, stir in the saffron. Add the mushrooms and warm them up. Peel and chop onions.
Heat the remaining fat in a large pot, fry the onion cubes in it until transparent. Add the spinach and let it collapse. Season with salt and pepper. Drain rice. Remove fish from the stock and drain.
Arrange rice, fish, spinach and mushrooms with the sauce on plates. Garnish with grated lemon peel.