Cut the pumpkin into slices, removing the seeds, and toss the slices in 2 tbsp of the oil in a roasting tin. Season and roast until tender, 20-30 minutes, then remove the skin from the flesh.
Heat the butter in a saucepan and add the cayenne, cumin and ginger. Cook for a couple of minutes. Put the pumpkin into this and mash it. Add the stock, lemon juice and zest, harissa and garlic. Season.
Heat 4 tbsp of the oil in a small frying pan and the gently cook the caraway seeds for about a minute. Add this, while it’s still warm, to the pumpkin mash.
To make the yogurt, chop the lemons – discard the seeds – and mix with the yogurt, brine and garlic.
Heat the rest of the olive oil in a frying pan and cook the onion until dark golden, even brown in patches. Add the mustard seeds and let them cook for a minute, then season.
Steam, boil or microwave the broccoli until it’s tender. Season.
Reheat the pumpkin mash and spread it out on a warm platter. Put the broccoli on top, then the preserved-lemon yogurt, and spoon over the onions. Sprinkle on the chilli. Drizzle a little extra-virgin olive oil over the top and serve.