Cut the butternut squash in half horizontally.
Scoop out the seeds, drizzle the olive oil over, and season with a bit of salt.
Roast in the oven at 200 degrees Celsius (390 Fahreneheit) for about 45 minutes or until the flesh is soft. While the squash is roasting, add the pancetta to a pan and cook it until brown.
When the squash is ready, scoop out the flesh, add it to a blender and blend until smooth.
Bring a pot of salted water to the boil, add the spaghetti and cook according to the packet instructions.
Reserve 2-3 tablespoons of water, and drain the rest. Take the spaghetti off the heat.
Beat the egg, add half of the parmesan to it, and add everything to the drained spaghetti and mix very well to combine.
Add the pureed butternut squash and reserved water, and mix again, then season to taste.
Top with the cooked pancetta, the remaining parmesan and parsley.