Wash and peel the ginger to remove all its skin. Cut it very nicely, or easier process it with the chillies in a food processor till nicely minced.
In a bowl, add jaggery, tamarind and one cup of water. Bring to boil till the jaggery is melted. Set aside.
In a sauce pan, heat the oil. Splutter the mustard seeds. Fry the curry leaves and the chilli flakes.
Add the minced ginger-chilli mixture and saute for five minutes or till the raw smell is gone.
Strain the jaggery tamarind water into the ginger mixture. Add another 1/4 cup and squeeze out the tamarind completely, pour the water.
Adjust the seasoning and simmer the mixture, stirring occasionally to avoid the mixture from sticking to the pan.
After some time, you will see the mixture getting syrupy. Cook till the mixture is nicely thick with little liquid and tastes done. Adjust salt and switch off.
Cool completely before storing into a clean glass jar. Use within a month and only use a dry spoon to serve.