Preheat oven to 190 C / Gas 5. Grease a casserole dish or baking tray.
In a saucepan, scald the mushrooms in salted boiling water for about 5 minutes. Remove, drain, then chop mushrooms finely. Combine with parsley and white sauce in a saucepan and cook gently with the mushrooms. Season.
Split eggs lengthways and take out the yolks. Put yolks into a bowl and mash.
In a small frying pan heat butter and oil and fry shallots. Strain and add to the mushroom sauce. Add a few spoonfuls of the sauce to the yolks and stir well. Dome each egg white half with the egg yolk and mushroom mixture. Place into a dish and spoon over the remaining sauce. Sprinkle the cheese on top.
Bake on one shelf above the centre for 8 to 10 minutes, until cheese is melted.
This recipe calls for "thick white sauce" and the shop bought white lasagne sauce would be good in this recipe.