Wash the salmon, dab dry and remove the skin. Season with 2 tablespoons lemon juice and salt. Sort and wash the spinach. Peel and dice onion and garlic and fry them in 20 g fat until transparent. Add the spinach and let it collapse. Season with salt, pepper and nutmeg
Sweat the flour in 40 g fat. Deglaze with broth and milk. Add lemon zest and simmer for 5 minutes while stirring. Season with salt, pepper and remaining lemon juice. Allow sauce to combine with egg yolk. Do not let it boil!
Put some sauce in a greased mould. Layer the lasagne sheets, salmon, lasagne sheets, sauce, spinach, lasagne sheets and remaining sauce. Sprinkle with parmesan. Spread the rest of the fat in flakes. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 40-45 minutes