Wash squash; cut in halves lengthwise, and remove seeds. Place squash, cut side down, in shallow baking pan; add a few tablespoons water to pan. Bake in hot oven (400°) 30 minutes. Turn cut side up; sprinkle with salt and continue baking 25 to 30 minutes, until tender.
Cook onions in boiling salted water, covered, about 30 minutes, or until tender. Drain.