There are 2 main types of Squash, Summer squash such as Courgettes and Patty Pan squash have a soft skin. Then there are Winter Squash
Winter squash are allowed to mature on the vine (all squash grow on a vine), then stored for use in winter. Because of their tough outer shell they keep well for long periods of time.
It tastes sweet, and yes there is a buttery note to its flavour. You will most likely have tasted it in soup and can be interchanged with pumpkin in most recipes and lends itself well to roasting with other vegetables. Butternut squash can also be puréed to make baby food.
It is very easy to peel if a Y style potato peeler is used and the peeler drawn towards yourself. Some folks cook it with the peel still on as it will soften. The seeds though edible are generally discarded.
Fresh and good quality butternut squash is a rich source of potassium as well as dietary fibers. One of the richest sources of Vitamin A, a cup or 100 gm of butternut squash can offer you 354% of RDA. It is also a great source of folates, vitamin C, E and K.
Butternut squash per 100g typically provides 42 calories, 0.1g fat, 8.3g carbohydrates, and 1.1g protein.