Clean and wash the soup greens. Cut celery and carrots into fine sticks, leek into rings. Peel and finely chop the onion. Heat the fat in a pot and fry the onions in it until transparent.
Add vegetables, also briefly sauté and deglaze with stock. Bring to the boil and simmer for 3-4 minutes. Meanwhile wash the chives, dab dry and cut into fine rolls. Season the vegetable stock with salt and pepper and divide into 4 plates.
Serve sprinkled with chives.