Bring sugar and water to a boil in a wide chrome steel skillet without stirring. Reduce temperature, gently bubble while occasionally moving the frying pan back and forth until a light brown caramel is formed, pull frying pan from the plate. Add onion and chestnuts, toss briefly in caramel sugar, pour in soup. Cover and simmer gently at low temperature for about 3 minutes until sugar is dissolved and liquid is honey-like.
Add butter up to and including celery, mix, season. Cover and simmer over medium heat for about five minutes.
It goes well with: Bread
Our tip: Use bacon with a fine, smoky note!