While spaghetti squash is best prepared in the oven, if you want a faster meal you can always put it in the microwave. Simply cut the squash in half and scrape out the seeds. Put it in a microwave-safe dish face down in half an inch of water. Cook around 20 minutes, or until soft.
Preheat the oven to 400°.
Prick the squash a few times with a fork and bake on a baking sheet for about an hour until it's slightly soft to the touch and you can easily pierce the skin with a fork or knife.
Let it cool and then cut the squash in half lengthwise, scoop out the seeds and discard. With a fork, scrape out the “spaghetti” threads into a bowl. Set aside.
In a large pan, heat the oil, gently stir in the spaghetti and heat through. Then add the scallions, garlic, salt, pepper, and ham. Cook, stirring carefully for two minutes.
Serve topped with Parmesan and scallions.