Preheat the oven to 375 degrees. Cut the acorn the squash in half and scoop out seeds and filaments. Set them, cut side up in a baking dish just large enough to hold them comfortably and pour hot water down sides of dish to come up about 1-inch up the squash. Bake for an hour or until entirely tender. Peel away skin and puree in food processor with maple syrup and butter; season to taste with salt, pepper and nutmeg.