I don't think you have a butternut squash, they are round and don't have necks. Sounds like you have either a summer squash or possibly a winter squash, is it bulbous on one end?
Anyway I would slice thin and marinate in garlic, a little olive oil, onion powder and any seasonings you like then grill for a short time on each side, or put in broiler but keep a watch on it and pull out when edges are browning.
Great side dish.
Now if it was butternut I would slice in half, scoop out seeds and add butter, maple syrup, some brown sugar and cinnamon and bake until fork goes easily through flesh and most of butter sugar mix has cooked into it.
You could have spaghetti squash, can you post a pic lol