Wash the potatoes and cook in boiling water for about 20 minutes. Then drain, quench, peel and slice. In the meantime wash and clean the mushrooms, dab dry and cut in half. Cut ham into fine strips and put aside. Peel and finely chop the onion. Heat the oil in a coated pan and fry the potato slices in it until golden brown. Add the onion and mushrooms and fry.
Season with salt and pepper. Beat the eggs until smooth, season with salt and pepper and pour over the potato and mushroom mixture. Let the mixture set slightly while stirring and form an omelette at the edge of the pan. Allow to set completely and turn out onto a plate. Sprinkle with the ham strips. Garnish with parsley, gherkin fan and cherry tomato quarters