Heat mustard oil in a pressure cooker. Add bay leaves, cinnamon, cumin seeds, chopped green chillies and green cardamom to it and stir well for roughly about 2-3 minutes.
Add thin sliced / chopped onions and cook on medium flame until the onions becomes translucent while stirring.
Now, add marinated mutton to it and toss well with onions. Cook for 4-5 minutes while stirring occasionally.
Include ginger garlic paste and sauté for a minute so that it mixes well with onions and mutton pieces.
Add all spices to it except coriander powder and crushed cumin/coriander/dry red chilli and mix well. Stir it occasionally and prevent the spices from burning.
Add in tomatoes and then salt, so that tomatoes release water quickly and turn mushy. Keep stirring on slow flame.
Add coriander powder and crushed cumin/coriander/dry red chilli and mix well. Keep stirring.
Add little water (half a cup) and keep stirring for 5-6 minutes so that all the spices get cooked well. Bear in mind to prevent the spices from burning.
As much as the curry you like, add water accordingly and mix well.
Cover the pressure cooker and cook it for 4-5 whistles and allow the cooker to release all the pressure automatically. Switch off the gas and open the lid and add chopped coriander leaves.
Transfer the scrumptious mutton curry to a serving bowl. Garnish it with chopped coriander leaves. Serve the hot mutton curry with rice or bread for your lunch or dinner.