Spray the saucepan with low-calorie cooking spray and place over a high heat. When the pan is hot, add the beef and cook the meat for 2-3 minutes until sealed and browned. Remove from the pan and set to one side.
Lower the heat to medium and give the pan another spray with low-calorie cooking spray. Add the onions, garlic, ginger and chilli and cook for 5 minutes until softened.
Add the garam masala, cumin and fenugreek, and stir for a minute until fragrant.
Stir in the tomato purée, coconut milk and stock.
Add the red peppers and butternut squash and add the meat back to the pan.
Increase the heat and bring to a boil. Cover and reduce the heat to a simmer, and cook for around 2 hours, stirring occasionally. If it looks to be drying out, add a splash of water (it should be fine if you have a tight-fitting lid).
After 2 hours, test the meat. It should be soft and falling apart. Keep covered and cook for longer, if needed.
Lightly crush some butternut squash with the back of a spoon and stir into the sauce to thicken it. Stir in the lime and chopped coriander and serve.