Preheat the oven to 180ºC/350ºF/gas 4. Grease a 1-litre loaf tin with a little butter, then line with greaseproof paper.
Cook the quinoa according to the packet instructions, then set aside to cool. Meanwhile, halve the squash, scoop out the seeds, then chop the flesh into rough 1cm chunks (you don’t need to peel the skin). Peel and roughly chop the onion. Peel and finely slice the garlic, then trim and roughly chop the celery.
Heat 2 tablespoons of olive oil in a large frying pan over a medium heat, then add the chopped vegetables and crumble in the chestnuts. Pick in the rosemary leaves, discarding the stalks, then toss well. Add the cayenne, paprika and oregano. Season, stir well, then reduce the heat to medium-low. Cook for around 15 minutes, or until softened slightly. Meanwhile, roughly chop the mushrooms, then add to the pan for the final 5 minutes of cooking.
Remove the pan from the heat, stir in the butter and grate in the zest from half the lemon. Transfer the mixture to a large bowl, then stir in the cooled quinoa, breadcrumbs, dried fruit and nuts (feel free to bash up some of the larger nuts if you prefer a less chunky consistency). Crack in the eggs, then stir well to combine. Pop the mixture into the prepared loaf tin, then place in the hot oven for 45 to 50 minutes, or until cooked through and set.
When there’s about 30 minutes to go, make the salsa rossa. Place a roasting tray on the hob over a medium-low heat. Prick the chillies and add to the tray with a lug of olive oil and the cinnamon stick. Peel and finely slice the garlic, peel and slice the onion into 8 wedges, then add them to the tray. Pick in most of the thyme leaves (save a few sprigs to one side), pour in the plum tomatoes and 1 tin’s worth of water, then stir well, breaking up the tomatoes with the back of a spoon. Season with salt and stir in the balsamic vinegar, then bring to the boil. Reduce the heat and simmer for around 20 minutes, or until thickened and reduced.
Once the salsa is ready, take 1 chilli out of the tray, then carefully halve, deseed and roughly chop it before returning it to the tray. Loosen the salsa with a splash of water, if needed, then pick out the extra chilli and cinnamon stick and put to one side. Remove the nut roast from the oven, then carefully turn it out, peeling away the greaseproof paper. Pop the nut roast into the tray and grate over the cheese. Place the cinnamon stick, chilli and reserved thyme sprigs on top, then return it to the oven for 10 to 15 minutes, or until bubbling and golden. Serve with mashed potato and seasonal greens.