In a wide bottomed, nonstick pan, heat the mustard oil to smoking point. Turn off and let cool completely.
In a bowl mix together yogurt,warter,salt,brown sugar,kashmiri red chilli powder and turmeric powder.
Place the pan with the cooled mustard oil on medium heat.Add asafoetida and onions.Saute and cook until onions turn brown.
Add curry leaves,ginger paste,garlic paste,green chillies and ground pickle spices.Saute for 5 minutes.
Add mutton and saute on high heat until mutton starts to turn brown.
Turn heat to simmer, add the yogurt-spiced water,cover with a tight fitting lid and cook until mutton is 3/4 done.
Add the chopped tomatoes, mix through,cover and cook until mutton is tender and cooked through.
Remove lid,increase heat to high and cook until all the water has dried up and the desired consistency is reached.
Add a dash of lemon juice.
Remove to a serving dish,garnish with chopped coriander leaves and serve hot along with Indian flatbread.
