Soak tamarind in a little hot water.
Put 4 to 5 cups water in a vessel and bring to boil. When it starts boiling, add the tomatos and close with lid. Cook for three minutes. Switch the stove off. Gently take out the tomatos and remove the skin. Allow to cool. Put this unskinned tomatoes along with soaked tamarind in a mixie and make a fine paste. Keep aside.
Grind the ginger to a fine paste.
In a small kadai put the fenugreek seeds and dry fry till it turn golden brown. Cool it and powder it finely.
In a kadai pour the oil and when it is hot, add mustard. When it crackles, add asafoetida powder. Add ginger paste and fry for a while. Then add the tomato paste along with red chilli powder and salt. Stir well. Add jaggery powder. Cook in low flame stirring now and then till it become thick and oil starts oozing out. Add fenugreek powder and mix well. Remove from stove and store it in a clean jar.
Stay good for weeks without refrigeration. Goes well with Curd Rice. Can also be served with Idli/Dosa/Chapathi.