1. Preheat the oven to 350º. Break down the squash by peeling the skin, scooping out the seeds and cutting the flesh into 1-inch cubes. On a foil-lined sheet pan, toss the squash cubes with the olive oil and season with salt. Cover the squash with foil and roast until it's tender, 50 to 60 minutes. 2. Purée the squash through a food mill or in a high-speed blender. Push through a fine-mesh strainer and allow to completely cool. Use immediately or store in an airtight container in the refrigerator for up to 5 days.