Meanwhile, peel and roughly chop the onion, peel the garlic and ginger, and dry-fry in a non-stick frying pan on a medium-high heat with the coriander and fenugreek seeds and the curry powder, stirring until lightly charred all over. Add the tomatoes and pineapple rings (reserving the juice), and cook for 10 minutes to soften and char, stirring regularly. Tip it into a blender, add the coconut milk and blitz until very smooth. Return to the pan, tip in the chickpeas, juice and all, and simmer gently until the sauce is thickened. Stir in the roasted squash, then season the curry to perfection, tasting and tweaking, and loosening with the reserved pineapple juice. Cool, cover and refrigerate overnight.