In a large soup pot, heat oil and saute onion, potatoes, and garlic until onion is just tender, about 3 minute Add spices and cook stirring for 30 seconds. Add 2 cups broth and bring to a boil. Reduce heat and simmer, covered, for 15-20 minuts, until potatoes are tender.
Add coconut milk and stir to mix. Transfer about half the soup to a food processor and process until smooth. Return to pot and add additional 1/2 cup broth if needed to thin. Stir in chickpeas and spinach and cook for 2 minute more, until spinach is just wilted. Season with salt and pepper, and serve hot.
Add more beans and spinach for a heartier texture. Round out the meal with warm pita bread, chutney, and cucumbers and shredded carrots topped with plain yogurt.