Peel and finely chop the onion. Clean and wash the cauliflower and divide it into small florets. Peel and wash carrots and cut them into fine sticks. Heat the oil in a pot and fry the onion.
Deglaze with broth and bring to the boil. Add cauliflower and carrots and cook for 8-10 minutes. Season to taste with salt and pepper. Wash chives, dab dry and cut into small rolls. Pour stock into soup bowls and serve sprinkled with chives.