Put the cauliflower in a colander, let it thaw, rinse with water and drain, peel the onion and cut into small pieces. Heat the oil in a saucepan and let the vegetables sauté briefly. Pour in the vegetable stock and let everything simmer for about 15-20 minutes over low heat, then add the cream.

Finely puree the soup with a blender. Season the cauliflower cream soup with salt and pepper. Spread the soup on plates and serve sprinkled with chives.