Pour the contents (except the curry leaves) of the dry spices into the Instant Pot Inner Pot (put the spices in one small area of the pan).
Pour the vegetable oil over the spices (just enough to soak the spices plus a little more).
Plug in the Instant pot, press ‘sauté’ and ‘adjust’ to ensure the digital display is on ‘more’. This is the high setting for sauté.
When you first hear the sound of the mustard seed “popping”, pour the diced green chilies, butter, and ginger into the pan. Add the curry leaves. Stir until the butter melts and chilies and garlic mixes well together.
Adjust the ‘sauté’ temperature down if needed. Sauté for another 1 min.
Add salt, pepper, rasam powder, turmeric powder and tomatoes. Add 2 cup of water to the pan. Mix them well and let them cook together. Adjust the sauté temperature as needed.
Ensure you stir periodically for uniform cooking and mixing of spices (just fold it over using a spatula). Stir just enough until all the spices are mixed with the tomatoes. Bring it to the first boil. Wait for a minute.
Turn off the Instant Pot
Add (1cup) Dhal to the Inner Pot, add (5 cups of) water,
On manual, under high pressure, with vent sealed, cook for 20 min. Let it cool down naturally.
On a bowl add tamarind, add a cup of water and microwave for 2 minutes. Once cool, make a puree and remove all pulps. Dilute the tamarind, if needed for the right consistency and keep 1.5 cup of tamarind juice aside.
Make sure there is no pressure in the cooker and the pin (pressure) is down. Open the Cooker lid, and be careful the dhal will be extremely hot.
Add the tamarind juice. Taste and add salt if necessary. Stir once, and close the lid. ‘Slow cook’ in high for 30 min.
Once done, squeeze ½ a lemon without seeds. Add in fresh cilantro for garnish.