Heat cooking oil in a pressure cooker and add panch phoran except for nigella seeds. Fry for a few seconds till the seeds splutter. Then add chopped onion along with nigella seeds.
Fry onion till light golden and soft and then add ginger and garlic paste. Fry for 1 minute.
Now add mutton pieces and cook with onion for 2 minutes followed by yogurt, red chili powder, coriander powder, and salt. Fry everything on medium heat for 5 minutes.
Add 1 cup of water or slightly more and pressure cook the mutton for 15 minutes.
Release the pressure on the cooker, open the lid, add brinjal and also taste and check the seasoning and adjust accordingly.
Now cook the brinjal with mutton without placing the lid or pressure. This will take about 10 minutes. Add more water if required.
Finally, add lemon juice and chopped coriander and cook for 1 more minute.
Pour the curry into the serving dish and serve with a tadka of dry red chili and curry leaves.
Tadka: Heat 1 tablespoon cooking oil in a small pan. Add dry red chilies and curry leaves and fry for 1 minute. Pour this tadka over the Achari Baingan Gosht.