The best way to cut butternut squash is to start with a large, very sharp knife and a sturdy cutting board. To begin, cut off the top stem and bottom end of your squash and discard.
Then cut the squash in half where the small, cylinder shape and round, bulb-shape meet.
Use a sharp knife (or a sturdy vegetable peeler) to carefully remove the skin. Alternatively, the skin can stay on because it's edible when roasted! But if adding to a soup (or recipe where it won't be roasted), remove and discard.
Remove any seeds with a spoon or ice cream scoop. The seeds can be cleaned, washed, dried, and roasted if desired (similar to this tutorial).