Peel onions and cut them into rings. Heat the oil in a pot. Fry the onions in it until golden brown. Deglaze with 1/2 l water and wine while stirring. Bring to the boil, stir in stock. Cover and simmer for about 15 minutes
Meanwhile grate the cheese. Roast bread in the toaster. Cut out 4 thalers (approx. 4 cm Ø each) from each slice or quarter the slices. Place on a baking tray lined with baking paper and sprinkle with cheese. Bake under the hot grill of the oven for 2-3 minutes (or place in the pan, cover and let the cheese melt)
Wash and chop the parsley. Season onion soup with salt, pepper and sugar. Fill into soup bowls, arrange with 2 cheese taler and parsley each