Finely dice the onions. Sauté in butter until translucent. Sprinkle with the flour and sauté briefly. Pour in the vegetable stock while stirring and let cook for 15 minutes.
Stalk, wash and roughly chop the herbs. Add the herbs and crème fraîche to the soup and puree finely. Season with salt, pepper and a little lemon juice.
As a starter for 4, as a main course for 2 servings.