With the rack in the middle position, preheat the oven to 350 °F (180 °C). Line a baking sheet with parchment paper.
Cut a small turban squash in half. With a spoon, scoop out the seeds. Lay the squash, skin side up on a baking sheet and cook for about 1 hour, or until the flesh is tender. In a food processor, purée the squash until smooth.