Preheat oven to 350 degrees. Pierce in several places with a fork. Place on rimmed baking sheet. Bake for 45 minutes to 1 hour, until squash gives when pressed. Turn over after 30 minutes. Cut squash in half; scrape out and discard seeds. Loosen squash strands, scoop out into a warm serving bowl. In a small nonstick skillet, saute shallots in butter over low heat until wilted, about 4 minutes. Pour over spaghetti strands and toss lightly. Food Exchange per serving: 1 VEGETABLE EXHANGE; CAL: 36; PRO: 1g; CAR: 6g; CHO: 3mg; SOD: 156mg;