Caramelize the sugar and remove the pan from the heat. Add the butter and melt. Then add the cabbage, onions, garlic and seasoning and sauté. Deglaze with the cider, and allow to simmer in an open pan for 10-15 mins. Allow to cool slightly.
Mix in the vinegar, oil, and chives and season.
Serve the salad still warm in cabbage leaves, and ladle on the Vacherin Mont-d'Or AOP.