Peel the onion, chop finely and pour hot water to remove the bitterness. Let it brew for 10 minutes, drain the water and squeeze the onion thoroughly. You can use pickled onions. To prepare the dressing. Mix the oil, salt, pepper, lemon balm and garlic powder.
Cut the cheese into small cubes. Mushrooms, if you take fresh, peel, wipe with a damp cloth and cut into small slices. (I took the canned food.)