Chickpeas and Potatoes in Creamy Coconut Sauce

When I made this, the ingredient list and steps seemed awfully complicated. But it’s worth it for the flavor of this coconut curry!
1 C dried chickpeas
1-1/2 t cumin seeds
2 t coriander seeds
1/2 t fennel seeds
1/8 t peppercorns
2 T chopped cashews
1 C yogurt, sour cream, or a mixture
2 t powdered ginger
1 C dried unsweetened coconut
3 T sesame oil
2 medium potatoes, diced into 1/2-inch pieces
1 t black mustard seeds
1 t turmeric
1-2 t salt
Pressure cook or simmer the chickpeas until they are soft. Drain, but save the cooking liquid.
Meanwhile, toast the cumin seeds, coriander seeds, fennel seeds, peppercorns, and nuts in a heavy frying pan over medium heat — watch carefully and remove when they are slightly darker. Transfer the toasted seeds and nuts to a spice grinder, blender, or mortar and pestle and grind them until they are powdered. In a blender, combine these spices with the yogurt, coconut, powdered spice mixture, and 1/2 C of the cooking liquid from the beans.
Heat the sesame oil in a deep frying pan and fry the potatoes until they are crispy and browned. Remove to a plate or bowl.
In the deep frying pan, cook the mustard seeds until they turn gray and start to pop. Then add the chickpeas, yogurt sauce, turmeric, and salt. Cook, stirring frequently, until sauce is reduced and slightly thickened. Fold in the potato cubes and heat through before serving.
Adapted from Nariyal Kabli Chana Usal in Yamuna Devi’s cookbook, The Art of Indian Vegetarian Cooking.