Cut the mushrooms into slices, and the onion into half rings. Fry together in oil until golden brown, salt and pepper at the end to your taste.
Divide boiled eggs into proteins and yolks. Proteins cut into plates. Yolks can be used elsewhere or also added to the salad.
Cut the fillet into pieces or disassemble into fibers.
Mix all the ingredients, add mayonnaise, season to taste and mix well.
Leave the salad for 10 minutes before serving.