Soak tamarind in water for 4-5 hours. Remove the pulp and keep it aside.
Rinse the turdal / pigeon / arhar dal well with sufficient water 3-4 times till the water runs almost clear.
In the washed dal, add finely chopped tomato, red chilli powder, turmeric powder and ginger-garlic paste.
Add 3 cups of water, mix everything well & pressure cook till 4-5 whistle or until the dal is perfectly cooked.
Whisk dal to smooth consistency.
Add slit green chillies, curry leaves, tamarind pulp and salt to sate. mix well.
Add water and adjust the consistency of the dal .
Let the dal come to a boil. Keep on stirring occasionally.
Meanwhile, lets make tadka (tempering).
In a tadka pan, heat oil. Add mustard seeds and let them splutter. Add cumin seeds and roughly sliced garlic cloves.
Fry the garlic till they turn light golden brown. Add dry red chillies, few curry leaves.
Our tadka is ready. Pour this tadka over the dal and mix well.
Let the dal boil for 6-7 minutes.
Add water as per the consistency you need. At this point to enhance the flavour of this khatti dal,you may also add a teaspoon of Garam Masala.
The more the dal boils the more flavourful it gets.
Lastly, add finely chopped coriander leaves.
Hydrabadi Khatti Dal is ready to serve.
You may keep some of the above made tadka aside and garnish it while serving. This is optional though.
Serve this delicious comforting Hydrabadi Khatti Dal with steamed rice along with some spicy Indian pickle, raita and papad.