Combine coconut and baking soda in a bowl, and toss well. Add 2 cups cilantro and next 4 ingredients; stir well, and set aside.
Using a melon baller, scoop a hole out of the center of each potato. Stuff the center of each potato with coconut mixture, reserving any remaining coconut mixture.
Heat oil in a large nonstick skillet over medium-high heat. Add cloves and cinnamon stick; sauté 1 minute. Remove spices from oil with a slotted spoon, and discard. Add onion to skillet; sauté 3 minutes or until tender. Stir in the cardamom and next 2 ingredients. Add potatoes to skillet, stuffed sides up; sprinkle with remaining coconut mixture. Combine water and yogurt; stir well. Pour over potatoes; bring to a boil. Cover, reduce heat, and simmer 40 minutes or until tender; remove from heat. Cut potatoes in half horizontally, and serve with sauce. Garnish with cilantro.