Wash the vegetables. Peel and dice the onion. Peel the carrots and cut them into thin slices. Cut the leek and the celery into thin slices as well.
Heat a large stock pot with olive oil. When hot, sauté the onion until translucent.
Add the vegetables and sauté for several minutes over medium-high heat. You want them to be slightly caramelized to add lots of flavors to the soup.
Add the water ginger, fennel seeds, cloves, peppercorns and salt to the water. Finally, put the whole chicken breasts into the stockpot.
Cover with a lid and simmer for 30 minutes over medium heat.