Rinse the thyme, spin dry and wipe off the leaves. Rinse, spin dry and finely chop the parsley. Peel and clean the onion and then dice it a little finer. Wash the peppers, remove the seeds and then chop finely. Clean the mushrooms and cut them into thick slices. Wash the lemon, rub the peel and squeeze out the juice. Preheat the oven to 200 ° C fan-assisted air.
Roast the bread slices on a baking sheet in a hot oven for about five minutes. Heat the olive oil in a pan and fry the mushrooms, onions and peppers for about four minutes. Season the mushrooms with lemon zest, lemon juice, thyme, salt and pepper and let them steep in the pan.
Take the bread slices out of the oven, cover with the cheese, then return to the oven for about 3 - 5 minutes until the cheese has melted.
Arrange the bread on plates, dust with a little paprika, pour the mushrooms on top, sprinkle everything with the parsley and serve immediately hot.