Cut the salsify and celery into cubes. Peel the onion, chop it finely and sweat it in butter. Add black salsify and celery and sauté with salt and sugar. Deglaze with vinegar, soy sauce and poultry stock. Let simmer for 10 minutes.
Remove the soup from the heat, add the condensed milk and crème fraîche and puree everything with the blender. Season to taste with salt and pepper.
Cut the chicken breast into 3 cm pieces and season with salt, pepper and curry. Fry in oil.
Put the fried chicken breast pieces on a wooden skewer and serve with the soup or simply add them to the soup.