1, buttercream means butter (the product of milk processing). Butter is a kind of solid oil processed from milk, which is the product of filtering some water from the upper layer of thick matter after mixing fresh milk. Mainly used as seasoning, rich in nutrition but high in fat, don't overdo it.
2. Fat-soluble nutrients in milk exist in milk fat, including vitamin A, vitamin D and a small amount of vitamin K and carotene. Therefore, butter is an excellent source of vitamin A and vitamin D, and its yellow color comes from carotene.