Clean the mushrooms and remove their stems. Chop them finely with the onion, sauté them in half the butter and after they cool, add them to the eggs beaten with the cottage cheese. Mix the blend with the grated cheese, chopped parsley and other spices.
Fill the mushrooms with this stuffing, arrange them in a greased tray and put a small piece of butter on each of them. Add 1 finger’s width of water in the tray and put it in a preheated 392°F (200 °C) oven, to bake for about 35-40 minutes.