1. Tip the coriander and cumin seeds into a small frying pan and set over a medium heat. Toast the seeds for 2 mins, shaking the pan, till they smell aromatic, then tip them into a large pestle and mortar. Crush the seeds till they're finely ground. Tip the ground seeds into a large bowl.
2. Peel the shallots and roughly chop them. Peel and roughly chop the garlic cloves and the ginger. Trim the ends off the chillies, if you're using them. Add the shallots, garlic, ginger and chillies to the pestle and mortar and crush together to make a paste. Add the paste to the crushed seeds.
3. Add most of the coriander, basil and mint leaves to the pestle and mortar (save a few of each herb for later). Add the sugar and vegan fischy sauce. Grate in the lime zest. Bash into a paste then add to the bowl. Stir everything in the bowl together well – this is your curry paste. If you don't have a pestle and mortar, you can blitz all the ingredients together in a food processor or very finely chop the veg and herbs and stir together with the whole toasted seeds to make a chunkier paste.
4. Pour 1 tbsp oil into a large pan and warm over a medium heat. Scoop the curry paste into the pan and cook for 2 mins, stirring frequently. Pour in the coconut milk and add the stock. Scoop in the peanut butter and stir well to make a creamy sauce. Slowly warm till it comes to a simmer.
5. While the sauce is warming, trim and peel the butternut squash. Halve the squash and scoop out the seeds, then slice the flesh into bite-sized chunks. Add the butternut squash to the sauce in the pan. Return the sauce to a simmer, then reduce the heat to low. Pop a lid on the pan. Cook the curry very gently for 1½ hrs till the squash is soft.
6. Trim the woody ends off the French beans, then cut them in half. When the curry has cooked for 1½ hrs, add the beans to the pan. Continue to cook for another 10-15 mins, lid off, till the beans are tender.
7. Just before serving the curry, add a good squeeze of lime juice to the sauce, and add the reserved herbs. Taste and add more sugar or fischy sauce, if needed. Divide the curry between bowls and serve with rice.