Preheat the oven to 400 degrees Fahrenheit. Using a large knife, carefully cut the spaghetti squash in half. Scrape out the seeds and save them for roasting if you'd like. Place the spaghetti squash in a baking pan cut-side down. Fill the pan with about 1/2" of water and cook for 45 minutes. Using a large spatula or tongs, carefully turn the squash over and cook for 15 more minutes, or until fork-tender. Allow the squash to cool.
Once the squash is cool enough to handle, use a fork to scrape the spaghetti squash strands out. Scrape the squash halves pretty clean until you're no longer getting strands of spaghetti squash. Season the spaghetti squash with salt and pepper and a little bit of butter or top with your favorite sauce.