Carefully pierce your spaghetti squash with a sharp knife 6-8 times all around.
Place it in the bowl of your slow cooker and cook for 3-4 hours on high or 6-8 hours on low.
Once the squash is tender, remove from the slow cooker and allow to cool slightly.
Once you can safely handle it, slice lengthwise and scoop out seeds.
Using a fork, scrape the flesh to create long strands.
Return the flesh to the slow cooker and turn it on low.
Add cream, garlic and butter; stir to combine.
Continue to cook on low, stirring occasionally, until thickened and creamy.
Add Parmesan and stir to combine.
Taste and season with salt and pepper appropriately.
Serve immediately topped with additional Parmesan and chopped parsley.