Preheat the oven to 375 degrees F. Line a baking sheet with aluminum foil or parchment paper.
Use a fork to poke several holes around the squash; this will allow steam to vent. Place the squash on the prepared baking sheet and cook for 50 minutes, or until a knife easily slides into the center. Remove from the oven and allow to cool for several minutes.
Once the squash is cool enough to handle, slice it in half lengthwise. Use a spoon to scoop out the seeds. Using a fork, gently rake the spaghetti squash strands into a large bowl.
Add the butter, salt, pepper, lemon juice, and parmesan cheese, stirring to combine the ingredients. Taste and adjust seasonings if desired.
Grate a bit more cheese on top before serving.
Notes
This recipe can easily be doubled using a larger spaghetti squash if you want to feed more people!