Marinate the mutton in salt, ginger garlic paste and green chilli paste. Keep for atleast 2 hours, preferably overnight.
Pressure cook the mutton for 35 - 45 minutes (3 - 4 whistles) until absolutely tender. Set aside.
In a saucepan, heat the oil and add the chopped onions. Sauce until translucent and soft.
Add in all the masala powders as well as the whole masala. Mix well and sauce for a further 3 - 4 minutes until the spice aroma starts wafting.
Add the mutton mince to this mixture as well as the tomato puree. Mix everything, cover and allow the meat to cook in its own juices (about 20 minutes). Do not add water as you want a dry mix.
Meanwhile, take the cooked mutton and shred it roughly. When the kheema is cooked, add in the mutton and stir until it is all mixed.
Add in the jaggery and the vinegar and balance the flavours so your pie mixture is both sweet and sour - just like a sali boti. Ensure that all the water has dried out and that you have a dry mixture.
Just before serving, empty the mixture into a baking tray and top it with a puff pastry sheet. Brush the pastry lightly with egg.
Preheat the oven to 250 degrees for 10 mins. Bake your pie at 250 for about 20 minutes until the pastry is crispy golden. Serve fresh out of the oven