Preheat Oven 400F. Cut butternut in half and remove seeds. Optionally, fill large baking dish with a half-inch of water. Place each butternut half face-down in dish. Prick with fork. Bake 45min until very tender. Puree in mixer, sparingly using water from cooking as needed. Use within 3 days or pour into ice-cube tray and freeze. Store in airtight-bag or container.