Extract 2 tsps of tamarind water from the tamarind and keep it aside.
Peel the garlic pods and boil it in ¼ cup of milk for about 2-3 mins.
Once this mixture has cooled, blend it along with the onion till it is a fine paste.
Pour about 2-3 tbspns of oil in a pan.
When hot add mustard seeds, once it pops add curry leaves and a pinch of asofetida powder.
Now add the ground onion mixture and saute the mixture till the raw smell is gone.
Add the tomato puree, sambhar powder, salt and turmeric powder.
Saute for about 2 minutes and then add a tbspn of tamarind water.
Boil for a minute and its ready.
Serve hot with pooris!!
Notes
Tamarind water that is added to the curry can be increased/decreased according to sourness of the tomatoes If you do not have sambhar powder, use about 1-1.5 tsps of chilli powder and 2 tsps of coriander powder instead.
Recipe by Spice Counter at http://spicecounter.com/sides/poondu-curry-garlic-flavored-curry/