Clean and wash the mushrooms and sprinkle them with the lemon juice. Peel and finely dice the onion and garlic. Heat the oil in a pan and fry the onion and garlic cubes in it until transparent.
Add the mushrooms and fry on all sides. Deglaze with sherry and season with salt and pepper. Let simmer for about 5 minutes. Wash parsley, dab dry and cut into strips. Add parsley to the mushrooms and arrange in small bowls.