Heat oil in a large stock pot or enameled Dutch oven.
Add the chopped squash, onion, potatoes, curry powder and salt and sauté for 5 minutes, stirring often.
Add the drained chickpeas, broth and whole (undrained) tomatoes. Bring the stew to a boil, cover, reduce heat and simmer for 30-40 minutes or until the vegetables are tender.
Add the raisins, taste the stew and add more salt if needed, cover and continue to simmer for 15 minutes longer.
Serve each bowl of soup with a dollop of plain Greek yogurt and a pinch of fresh cilantro. Enjoy!