Cut the cleaned mushrooms into slices and the onion into small pieces.
Put a few leaves of the lettuce aside for the garnish and cut the rest into small pieces.
Halve the two feta cheeses and let them drip off a little on kitchen paper.
Heat 3 tablespoons of oil in a pan, add the mushroom slices, season with salt and pepper, stir and fry for about 4 minutes. Then add the sliced onion and fry for another 3 minutes.
Now add the cut lettuce to the mushrooms and sauté briefly, then stir everything and remove the pan from the heat.
Heat 2 tablespoons of oil in another pan, add the cheese halves, sprinkle with the herb mixture and fry briefly. When the underside begins to melt, turn the cheese halves and add the herb mixture again.
Fry the cheese for a total of approx. 5 minutes, turning it several times, then removing it from the pan and serving with the mushrooms.
For the breaded version, turn the cheese halves in the beaten egg and breadcrumbs before frying.