Preheat your oven to 425 degrees f.
Place your butternut squash halves cut side up in a baking dish large enough to hold both halves.
Drizzle with oil and sprinkle with sea salt and pepper, then rub it all in evenly.
Bake your squash for 35-45 minutes or until until just fork tender.
Remove your squash from the oven and let it cool slightly, until you can safely handle it.
Using a spoon, carefully scoop out most of the the flesh from your squash into a large bowl, leaving about 1/4 inch border around the squash halves. This step needs to be done carefully, as not to break the outer skin/shell.
Add in Greek yogurt, 1/2 cup of parmesan cheese, sea salt and pepper over the roasted squash in the bowl.
Using a fork, mash and mix thoroughly to combine everything together with the squash flesh. We want a nice, creamy texture here.
Spoon this squash mixture back into the "skins/shells" and sprinkle the tops with remaining parmesan cheese as shown.
Return your dish into the preheated oven, and bake for 10 minutes, or until heated through, then broil for a couple of minutes more until nicely golden brown on top.
Serve immediately and enjoy!