- With the rack in the middle position, preheat the oven to 190 ° C (375 ° 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 45 minutes to 1 hour or until the squash is tender with the tip of a knife. Let cool.
- Remove the flesh with a spoon.
- Meanwhile, in a small saucepan, gently heat the butter until it turns golden brown. Immediately pour into a bowl to stop the cooking. Keep the brown butter aside.
- In a food processor, purée the squash flesh with the remaining ingredients. Season with salt and pepper.