Wash and keep the avarekalu ready. Wash and peel the skin of potato, cutting it into 4 large chunks. Wash and cut brinjal into chunks.

In a pressure cooker, add avarekalu, chopped brinjal, and peeled potato cubes along with required water and salt. Pressure cook for 2 to 3 whistles until soft. Set aside.

Soak tamarind in a cup of water. Brush the whole onion (with skin) with a little oil. Hold the onion with tongs and roast it over direct flame on low to medium heat until the outer skin turns black. Let it cool. Similarly, roast the greased whole garlic bulb on all sides until its skin chars black. (Refer to Notes if you prefer stove-top sautéing).

Peel the charred outer skins off the roasted onion and garlic. In a blender, grind them to a smooth paste along with the soaked tamarind, grated coconut, red chilli powder, dhania powder, turmeric powder, and fresh coriander leaves.

Add the ground masala paste to the cooked avarekalu, potato, and brinjal pieces. Check consistency and seasoning, adding a little water or salt if needed. Simmer the gravy for 5 to 7 minutes until it thickens and the raw spice aroma disappears. Heat oil in a small pan, splutter mustard seeds, cumin seeds, urad dal, and curry leaves, then pour the tempering into the gravy. Mix well and serve hot with steamed rice!