Heat the oil in a large frying pan and gently fry the onion for 5 minutes, or until lightly browned, stirring frequently. Add the garlic and curry paste and cook for 30 seconds more, stirring constantly.
Transfer to the slow cooker and add the butternut squash and carrot. Sprinkle over the flour and toss together. Add the tomatoes, chickpeas, frozen spinach, sugar and stock.
Stir well, cover with the lid and cook on low for 9–11 hours, or until the vegetables are tender and the spices have mellowed. Stir well before serving with freshly cooked basmati rice, yoghurt and assorted chutneys and pickles.
