Place the sweet potatoes in a large saucepan, add water to cover and salt to taste. Boil until the potatoes are tender, about 25 minutes, drain and let cool a bit in their skins.
Peel the sweet potatoes and slice them about 5mm thick. Put them in a serving bowl and while still warm sprinkle with the onion, parsley, tarragon, basil, thyme, chives, wine, stock, vinegar and oil. Toss and add salt and pepper to taste.