Peel onions, halve them according to size and cut them into thin rings. Heat the oil in a large pot. Fry the onions until golden brown, turning them over. Dust with flour and sauté. Stir in 2 1/2 l water and stock, bring to the boil. Simmer everything for about 15 minutes.
Grate the Gouda finely, add the Gouda and processed cheese in flakes to the soup and melt while stirring. Season the soup with pepper and salt if necessary. Wash the parsley, cut into strips and sprinkle over the soup