Cut the meat into thin strips, fry in hot fat and remove from the pan. Chop the onion and fry in the pan, sprinkle with flour. Add the mushroom liquid while stirring and simmer for 10 minutes. Add the meat, mushrooms and peas, stir in the cream and season to taste with salt, pepper and lemon juice.
Put in a baking dish, sprinkle with cheese and bake in the oven (electric stove 200 °) until the cheese has melted.