1. Warm oil in a large pot over medium-low heat. Add cumin seeds; stir until fragrant, about 10 seconds. Add onion and garlic; sauté until onion is soft and beginning to brown, about 10 minutes. Add ginger, coriander, turmeric and 1 tsp. salt; sauté 2 minutes longer.
2. Stir in broth and potatoes, raise heat to high and bring just to a boil. Reduce heat to low and simmer for 5 minutes. Stir in carrots, cauliflower and chickpeas. Cover and simmer until vegetables are cooked through, about 12 minutes. Stir in coconut milk and cook 5 minutes longer.
3. Taste and season with salt and pepper. Serve stew over rice, garnished with chopped cilantro, if desired.
Make it ahead
TO FREEZE: Let cool; transfer to a freezer-safe container (leave 1/2-inch space at the top); freeze.
TO SERVE: Thaw in refrigerator overnight. Reheat in a covered pot over medium-low heat, stirring, until warm, about 40 minutes.