Squash with cardamom & nigella seeds

Mary Ann Grant (inspired by Yotam Ottolenghi)Ingredients20g unsalted butter1 tbsp olive oil1 large red onion, peeled, halved and cut into 1cm-thick slices (170g)Squash or pumpkin (about 1.2kg), peeled and cut into 3cm chunks30g pumpkin seeds1¼ tsp nigella seeds1 tsp ground cumin1 tsp ground coriander¼ tsp ground turmeric4 cardamom pods, lightly crushed1 large cinnamon stick2 green chillies, halved lengthways½ tbsp rice malt syrup200ml vegetable stockTo serve:Some Greek yoghurt or labne1 tbsp basil, chopped (or coriander)saltHeat the oven to 200C.MethodPut the butter and oil in a large sauté pan, and fry the onion for eight minutes over medium heat until soft. Add the squash/pumpkin, turn the heat up to medium-high and cook for 10 minutes, stirring occasionally, until it starts to colour.Remove from the heat and add half a teaspoon of salt, the seeds, spices, chillies and rice malt syrup. Mix and transfer to an ovenproof dish large enough to hold everything snugly.Pour in the stock and roast for 30 minutes, by which point the squash should be tender and all the liquid absorbed or evaporated.Serve warm with yoghurt/labne spooned on top, a sprinkling of chopped basil and a few nigella seeds.