Pumpkins have a rustic reputation belied by their appearance in this silky and sophisticated dish, which is happily very easy to rustle up. You could roast the pumpkin first, rubbed in oil and salt.
Melt the butter in a saucepan and turn in the pumpkin and onion, stirring them for a few minutes on medium heat.
Add the sugar, pour in enough stock to surround but not drown the pumpkin, bring to a gentle simmer and cook, covered, for 15 minutes until the pumpkin is soft.
Mash the pumpkin with a potato masher or a blender and return to the pan. Add salt,