Spray a large saucepan or casserole with cooking oil spray and place over a medium-high heat. Add the onion and cook gently for 12–15 minutes.
Add the meat, garlic, ginger, chilli, butternut squash, peppers and curry powder, and stir-fry slowly for a few minutes. Pour in the measured water and stir well.
Bring to the boil, cover tightly and reduce the heat to low. Simmer gently for 50–60 minutes until the meat and squash are tender. Season to taste, stir in the coriander and serve hot with rice.