Firstly, soak tamarind in water for close to 30 minutes or until it dissolves completely. Then extract water and keep it aside.
Meanwhile, clean ginger and grind it into a paste.
Heat oil in a kadai. Add mustard seed followed by ginger paste. Roast the ginger in the oil just for 30 seconds.
With this add the tamarind extract, salt, and jaggery. Cook for close to 10 minutes or until the water is evaporated and the pachadi becomes dry.