Lotus root in roasted-cumin yogurt sauce

The diversity of Raghavan Iyer's cookbook 660 Curries is extraordinary.  The book has no fewer than three recipes for lotus root--a vegetable I have not encountered at any Indian restaurant.  This excellent recipe calls for simmering chopped lotus root on a base of sauteed garlic, ginger, and green Thai chilis and then bathing it in a sauce of yogurt, heavy cream, ground roasted cumin, and chopped cilantro.