Sprinkle the fish with lemon juice and refrigerate. Cut the carrot into rounds and unwrap the broccoli and cauliflower bunches and bring to a boil for 5 minutes. Heat 30 g butter in a pan and cook the diced peppers, then add the carrots, broccoli and cauliflower. Salt and pepper to taste.
Melt 20 g butter, sprinkle with flour, stirring and gradually pour the cream. Allow the sauce to thicken, then add the yolks, lemon juice, salt and pepper. Stir until the composition is homogeneous.
In a heat-resistant dish, greased and lined with breadcrumbs, layer the vegetables and fish, with sauce between them. Sprinkle with cheese. Place the dish in the preheated oven for 45-50 minutes at 170 degrees C.