Pre-heat the grill or a broiler. Grill or broil the chiles until the skin begins to blacken, 5 to 7 minutes. Transfer to a bowl, cover with plastic wrap, and let steam until the skin loosens, about 10 minutes. Peel the chiles and chop coarsely. Set aside In a small sauce pan, add the potatoes and enough water to
cover and cook until tender. Drain and set aside.
In a large sauce pan, heat the oil, cumin, onion, celery and pepper and sauté until the vegetables are softened, about 5 minutes. Add salt and corn and cook for 3 to 4 minutes longer.
Stir in the roasted chiles, potatoes, stock, cream, curry powder and 1 tablespoon of cilantro and simmer until the soup thickens, 20 to 25 minutes.