Cut the meat into 2cm cubes
In a wide heavy pot, heat the half the ghee, or oil over medium-high heat. Add the Patch Phoron and cook for about 30 seconds, or until the mustard seeds have popped.
Add the the Bhuna spice and stir-fry for 30 seconds. Add the sliced onions, reduce the heat to medium, and cook, stirring frequently to prevent sticking, until well softened, about 10 minutes.
Transfer mix to slow cooker.
Heat the remaining ghee or oil and add the meat in batches until browned on all sides. Transfer to slow cooker.
Deglaze pan used with water and add to slow cooker, along with passata, lime juice, sugar and salt and chillies.
Cook for 6 Hours
Before serving stir in half the coriander
Serve with steamed rice, Bengali salad/ or steamed vegetables and flatbread. Top with sprinkled coriander and a squeeze of lime.