Simmer squash in water with 1 teaspoon salt in a 5-quart pot (water will not cover squash), covered, until squash is very tender, about 15 minutes.
Reserve 1/2 cup cooking liquid, then drain squash in a colander. Puree squash, syrup, oil, and butter in batches in a food processor until smooth, adding reserved cooking liquid if puree is too thick. Transfer to a serving bowl and stir in pepper and remaining 3/4 teaspoon salt. Before serving, drizzle with Roasted Pumpkin Seed Oil.
Tested in Fall Harvest cooking class