step 1 Heat oven to 200C/180C fan/gas 6. Toss the pumpkin or squash in a roasting tin with half the oil and seasoning, then roast for 30 mins until golden and tender. step 2 Meanwhile, put the remaining oil in a pan with the onion, ginger and lemongrass. Gently cook for 8-10 mins until softened. Stir in the curry paste for 1 min, followed by the roasted pumpkin, all but 3 tbsp of the coconut milk and the stock. Bring to a simmer, cook for 5 mins, then fish out the lemongrass. Cool for a few mins, then whizz until smooth with a hand blender, or in a large blender in batches. Return to the pan to heat through, seasoning with salt, pepper, lime juice and sugar, if it needs it. Serve drizzled with the remaining coconut milk and scattered with chilli, if you like.