This deeply satisfying coconut-yogurt dish is wholesome, bright and loaded with vegetables. It comes from Kerala, in southern India, where ingredients like mustard seed, curry leaf and coconut are common. In many traditional versions, the curry leaves and mustard seeds are mixed into the stew; in this one, they are tempered in coconut oil and drizzled over the top, to add an extra shot of richness and crunch.
In a large, deep skillet, add the veggies, plus a thin layer (about a centimeter or 1/3 inch) of water. Stir in the turmeric and 2 teaspoons salt. Bring to a boil over high heat, then turn the heat down to medium and cook, uncovered, until you can pierce the vegetables with a fork but they are still slightly firm, 5 to 7 minutes.
While the vegetables are cooking, combine the coconut, chiles and cumin seeds in a food processor, blender or mortar and pestle and blend or pound until coarsely ground.
Once the vegetables are done cooking, turn the heat down to low and add the coconut mixture, yogurt and 1 cup water. Cover and cook until the vegetables are soft and fully cooked and the coconut mixture, yogurt and water have come together as a sauce, 12 to 15 minutes. Taste and add more salt, if necessary.
Melt the coconut oil in a small saucepan or butter warmer over medium heat. Add the mustard seeds and as soon as they start to pop and dance around in the oil (1 to 2 minutes max), take the pan off the heat and add the curry leaves. They will start to pop and crack, but within seconds, they’ll settle down and crisp up.
Pour the coconut oil mixture over the avial. Serve with rice.