The fillet is washed and portioned. The spinach is cleaned, chosen leaf by leaf, washed and soaked in boiling salted water. After soaking in boiling water, the spinach is chilled; we choose the big leaves and separate them from the stalks. The remaining leaves are passed through the meat grinder or chopped. The flour is bolted. The milk is boiled. The eggs are washed, disinfected, passed through a cold water jet and blended in a pan. The pressed cheese is grated. The lemons are washed and squeezed. The onion is peeled, washed and chopped.
The butter is melted. When is hot, we add the flour with water and the milk. We boil a short time and we add milk again and the eggs. We keep it on the stove for 15 minutes mixing continuously at medium heat. To the half of the mixture we add the chopped spinach, salt, pepper and after mixing we boil ten minutes more. After boiling, the spinach composition is placed like a layer on a tray, add few leaves of spinach soaked in boiling water then the fish pieces (boiled in water with salt, onion, peppercorns-chilled in the same water it was boiled and drained on a sheet). On top of the fish we arrange the spinach leaves soaked in boiling water, sprinkle with salt and pepper and we add the wine. On top we poured the rest of the white sauce and sprinkle with grated pressed cheese. We put into the oven for 15 minutes to gratinate.