Preheat the oven to 350ºF. Cut the butternut squash in half lengthwise and remove the seeds. Place cut side down on a rimmed baking sheet and add 1 cup water. Bake until the squash is fork tender, 30-35 minutes. Reduce the oven temperature to 325ºF.

Scrape the flesh from the cooked squash and place it in the blender. Puree until smooth, scraping down the sides of the blender as needed. Add the coconut milk, eggs, maple syrup, and salt. Blend until smooth.

Pour the mixture into a 1-quart baking dish and place the baking dish in a roasting pan. Fill the roasting pan with boiling water to reach halfway up the side of the baking dish. Bake for 1 hour.

Cool completely. Serve with whipped cream or dairy-free whipped topping, if desired.