Using a sharp knife, carefully cut the stem end from the spaghetti squash. Pierce the squash in several places with a fork or knife. Place it in a microwave-safe baking dish and microwave on full power for 3 minutes—this will make it easier to slice in half.

Remove the squash and slice it in half lengthwise.

Use a spoon to scoop out the seeds and scrape out any loose membranes. Brush with olive oil or melted butter and sprinkle lightly with salt and pepper.

Place the squash halves, cut sides down, in the baking dish, and add about 1 inch of water.

Microwave on full power for 8 to 12 minutes, depending on the size of the squash and your microwave oven.

Test the squash with a fork. It should be tender enough to penetrate the skin with only slight resistance.

Remove the baking dish from the microwave oven, drain, and flip the halves over.

With a fork, gently scrape the insides of the halves to loosen the "spaghetti" strands.

Serve hot or refrigerate the squash and reheat later.