Peel and chop the onions. Peel, clean and chop the turnip, potatoes and carrot. Heat oil in a pot. Lightly caramelise the sugar in it. Fry the onions briefly. Add prepared vegetables and steam.
Pour in the broth. Simmer covered for about 25 minutes. Then puree finely, season with salt and pepper.
In the meantime, pluck the Parma ham into pieces and place them on a baking tray lined with baking paper. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 4 minutes.
Take out and let it cool down. Wash parsley, shake dry. Pluck leaves from the stalks and chop finely. Stir crème fraiche until smooth. Arrange soup with crème fraîche and ham chips, sprinkle with parsley.