Heat coconut and jaggery in a heavy frying pan. Cook on low heat, stirring frequently. Cook till most of the moisture evaporates and the coconut and jaggery start binding together, about 10 minutes. Sprinkle in the milk powder, and stir well to mix. The milk powder helps absorb moisture and bind the mixture. Coconuts vary in their water content. If the mixture is still too loose, add a bit more milk powder. Add cardamom powder and mix.
Grease a rimmed plate or thali with some ghee. Spread the mixture evenly and press and flatten with your hands. Cool completely. Cut into desired shape and serve.