Preheat your oven to 350 degrees.
Cut the ends off the butternut squash and then cut the squash in half. Remove the seeds from both halves.
In a 9 x 13 baking pan, place the squash flesh side down. Add about 1 inch of water to the pan and cover with tin foil. Place in the oven and bake for about 30 to 40 minutes. I like to check to see if it's done by sticking a knike in the upper part of the squash. It should slide in easily - though it is better to be more firm than soft since we will be placing it back in the oven once all the ingredients are added.
Remove the squash from the 9 x 13 and allow to cool enough to you can handle it.
In a baking dish, scoop out the squash and add the sour cream, parmesan and salt and pepper. To be honest, I don't measure these ingredients, so add whatever feels right to you. I want to squash flavor to come through so I am careful with the sour cream for sure. Mix well.
Place the baking dish in the over, uncovered and bake for 10 more minutes.
Serve and ENJOY!