Spray the frying pan 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. Add the meat to the slow cooker.
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.
Add this to the slow cooker along with the tomato purée, coconut milk and stock.
Add the red peppers and butternut squash and stir well.
Cook on low for 7-8 hours (or high for 4-5) until the meat is tender and easily falls apart.
Lightly crush some butternut squash with the back of a spoon and stir into the sauce to thicken it. Stir in the lime juice and chopped coriander and serve.