Bring a large pan of salted water to the boil, add the pumpkin cubes, then reduce the heat and simmer for 15-20 minutes, or until the pumpkin is tender to the point of a sharp knife. Drain well and return to the pan. Shake the pan over low heat for about 1 minute to dry out the pumpkin.
Pass the pumpkin through a mouli sieve or food processor to purée finely, t