The squash may be baked in the oven or microwave. If you are going to use the oven, preheat it to 375 degrees.
Cut the squash in half lengthwise. Place the halves in a baking dish, cut-side up with about 1/4 inch of water, and cover. Bake until easily pierced with a knife, about 45 to 50 minutes. Or microwave until easily pierced with a knife, about 10 minutes.
When the squash is cool enough to handle, scoop out and discard the seeds. Scoop out the pulp and transfer to a serving container. Add the margarine, and stir in to melt. Mash the squash until smooth. Stir in the nutmeg and season with salt. Reheat in the microwave or oven just until heated through, and serve.
This recipe yields 6 servings.