Clean the mushrooms and rub with kitchen paper. Cut the mushrooms into slices. Cut bacon into small cubes. Peel and finely dice onion. Put bacon in a hot pan and take it out.
Add oil to the frying fat and heat. Fry the mushrooms for 4 - 5 minutes. Clean, wash and halve the tomatoes. Add to the mushrooms 1 minute before the end of cooking time. Season with salt and pepper. Add bacon, onion and vinegar.
Season to taste with sugar. Clean, wash and drain the salad. Wash and drain the parsley and chop finely. Arrange salad and mushrooms on a plate. Serve sprinkled with parsley.