Transfer the cut vegetables to the pressure cooker.
Wash the dal (yellow pigeon peas) to the pressure cooker.
Add the salt and all spices - mix well.
Add the water and mix well.
Close the pressure cooker with the lid. Make sure you put the safety valve and follow all directions mentioned in the manual of the pressure cooker.
Cook for about 10 minutes or until 3 whistles have come.
Switch off the pressure cooker after 10 minutes and wait for it to cool down.
Meanwhile make tamarind extract by dissolving the tamarind paste in half a cup of water for about 10 minutes. Once the tamarind is dissolved, you can filter the tamarind extract and keep it aside. (you can skip using tamarind if you are using at least 3 tomatoes in your vegetables).
Once the pressure cooker is cooled, you can open the cooker and see if the lentils and vegetables are cooked well and are soft enough.
Add the tamarind extract to the cooker, mix well and heat for another 1 to 2 minutes stirring occasionally. You shouldn't close the cooker at this time, just keep it open and cook for 2 minutes.
Now your sambar is ready with the blended dal, vegetables, spices and tamarind extract.The only step remaining is to make the seasoning which we will do now.
Heat oil in a pan and add mustard seeds.
When the mustard seeds splutter, add red chilies and curry leaves fry for a few seconds.
Pour this seasoning on the sambar and gently mix the contents. Delicious and simple sambar using spices is ready to serve!
Notes
You can serve this sambar with rice, dosa or idli for vegetarian lunch or dinner.