Heat oil in a pressure cooker/flat bottom pan and add the sliced onions.
Fry the onions on high/medium heat for 10 mins till golden brown in color.
Add the marinated mutton and bhunno/fry on high heat for 3 mins.
Add the ready made Meat Masala, mix well and continue to fry/bhunno on medium heat for another 2-3 mins.
Now, add the chopped tomatoes and cook on medium to low heat for 3 mins till the tomatoes are soft.
Add the cut green chilli, mix and add 200 ml water. Mix well.
Close the pressure cooker & pressure cook till 3-4 whistles (on high heat till 1st whistle and then on low heat for the balance 3)
Allow the pressure cooker to release pressure on it’s own.
Remove lid and simmer for a few mins for the gravy to reach the desired consistency.
In case you’re cooking in a flat bottom pan, cover & cook on low heat for another 45-60 mins till the meat is tender. Remove cover few times, give a stir and add more water if and when necessary.