Set the instant pot to a sauté mode and add oil. Once it is hot, add chilies, black pepper corn, and seeds, and allow them to splutter.
Now add Asafoetida and curry leaves. Once the curry leaves are cooked, add ginger and allow them to cook well while infusing their flavors in the oil.
Add chopped tomatoes and mix well. When tomatoes are mushy(say 5-minutes), add the spice mix and stir well.
Now add toor dal and 4 cups of water. Add salt and tamarind Pulp and mix well.
Add salt and close the lid while sealing the vent.
Set the instant pot for 10-minutes of pressure cooking. After the cool time, allow for natural pressure release before opening the lid.
Now mix in fresh cilantro. Add four more cups of water and bring the mixture of a boil. Rasam is always very thin and broth-like. Adjust salt if necessary at this point.
In a small tadka pan, add a teaspoon of oil and add garlic when the oil is hot.
Once the garlic is cooked, add pepper and cayenne pepper and allow it to infuse well.
Turn the heat off and pour this tadka over the Rasam and mix well.
Serve Rasam hot.