With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line a baking sheet with parchment paper.
On a work surface, cut the squash in half lengthwise and remove the seeds. Season with salt and pepper. Place on the sheet, cut side down, and cook for 1 hour or until the squash is tender with the tip of a knife. Let cool.
Remove the flesh with a spoon. In a food processor, purée the squash with the remaining ingredients until smooth. Season with salt and pepper.
Serve with Maple Syrup Glazed Pork Tenderloin, Maple Grilled Chicken or a veal, beef or lamb roast.