Grind together onion, garlic and cumin and pepper powder along with red chilli.Keep the paste aside
Heat oil in a pan add the paste then add all the masalas and stir add sim and potato add little water and allow it to cook until done

Add turmeric and salt to prawns and fry it and keep aside.when the sabji gets tender add fried prawns and let it cook.

Serve with chopped coriander leaves