Soak tamarind in a small quantity of hot water.
Add ½ cup of water to it, crush well and squeeze the essence out. Repeat this process 2 or 3 times more.
Fry mustard in oil on a medium fire. As the spluttering is about to subside add fenugreek.
When the spluttering subsides add asafoetida and turmeric followed shortly by green chillies and fresh ginger.
Sauté for a while and add tamarind essence [or paste with 1 cup of water].
Add salt [also asafoetida and turmeric if not used in the tempering] and allow it to simmer on a low fire.
Add jaggery and cook stirring at intervals.
When it attains a semisolid consistency, remove from heat, allow it to cool and store in a clean, dry container.
Serve with chappathi, poori and the like or with dal - rice, curd rice or rice mixed with mulaku koottal of Kerala.