In a saucepan, bring water or vegetable broth to a boil over high heat.
While the water is heating, rinse and cut the cauliflower head into small florets. Peel potatoes and cut them into small cubes. Transfer the cauliflower florets and potato cubes into the boiling water. Reduce the heat to medium-low until the water is boiling again. Cover with lid and simmer until the potato cubes are easily pierced with a fork, approximately 8 minutes.
While the cauliflower and potatoes are cooking, cut the leek lengthwise first and then slice it. If you prefer the soup to have a pale color, remove the green part of leek and only use the white stalk. Swish the sliced leek in water and strain. Heat a sauté pan over high heat until hot. Add olive oil and wait for 30 seconds until the oil is hot. Add the well-drained leek and remaining ingredients into the oil. Saute until the leek is soft and fragrant.
Once the cauliflower and potato are cooked, transfer the leek into the saucepan and continue to simmer for 2 more minutes.
Remove the saucepan from heat. Use a hand blender to puree the soup. Garnish with sliced pepper and chickpeas. Serve immediately.
For roasted chickpeas, see recipe here: http://lightorangebean.com/roasted-chickpeas-quinoa-veggie-bowl/
Cauliflower Soup with Leek and Potato https://lightorangebean.com/cauliflower-soup-leek-potato/