Cook the corn in salted boiling water until it starts to soften. Drain and return to the pan.
In a food processor, blend the cilantro, chilies, ginger, garlic, and coconut to a paste. Add the paste to the corn with enough water to make a sauce. Bring to a boil, reduce the heat, cover, and simmer for 10 minutes. Add the coconut milk and gently simmer for 5 minutes more.
Meanwhile, melt the ghee or butter or heat the oil in a small skillet over medium heat and add the mustard seeds. When they start to pop (a matter of seconds), add the curry leaves. Remove from heat and pour over the curry - it will make quite a loud crackling noise, so stand back a little. Add salt and garnish with more cilantro leaves.