Finely dice the onions. Peel the potatoes and parsnips and cut into 2 - 3 cm pieces. Heat 30 g butter in a large saucepan and sauté the onion in it over a medium heat for 3 minutes until translucent. Add the potatoes and parsnips and cook for another 3 minutes while stirring. Add the bay leaf, wine and stock and bring to the boil, covered. Add the cream, cover again and bring to the boil over a mild heat for 30 minutes.
Sixth 100 g chestnuts. Caramelize the sugar in a pan until light brown. Pour in 80 ml of the broth. Be careful, it splatters! Stir in the prepared chestnuts and cook over a mild heat until the liquid has almost evaporated. Stir in the remaining butter. Season the chestnuts with a little allspice and nutmeg and set aside.
Cut the parsley very finely. Cut the cress briefly under the leaves from the bed and mix with the parsley and a little oil.
Heat the remaining chestnuts in the soup for 5 minutes. Puree the soup very finely with a cutting stick or in a blender and season to taste with 1 - 2 squirts of lemon juice.
Pour the soup into preheated plates, garnish with the caramel chestnuts and some of the herb oil and serve.