Soak tamarind in 1/2 cup of hot water for 10 mins. Extract pulp and keep aside.
Wash and soak tur dal for 10 mins. In a pressure cooker, place the dal, turmeric powder, enough water and cook for 2-3 whistles till the dal is soft. Mash well and keep aside.
Place the peeled garlic in a mortar and just pound them once with the pestle. The garlic should just have a crack, just enough to let out its aroma. You can do them individually too if you do not mind the time it takes. Keep aside.
Heat oil in a pan. Add mustard seeds and when they crackle add vengaya kari vadagam, asafetida, broken whole dry red chilies and sauté for 1/2 minute.
Add the tamarind pulp, salt and the garlic pods. Let it come to a bubbling boil.
Add sambar powder, mix well and cook over medium flame for 2 minutes till the raw smell goes off.
Add the mashed tur dal, mix well, simmer the flame, close with a lid and cook for 5-7 mins. The flavors would have merged by now.
Transfer to a serving bowl, add fresh curry leaves, mix well, close with a lid and let it rest for 5 minutes.
Poondu Sambar is ready to be served with hot steamed rice.